Maps, maps, maps (pt. 2/2: Australia)

Guillaume Brouscon world map, 1543
Guillaume Brouscon world map, 1543

Yes, the answer to Tuesday’s final query is that the Dieppe maps, (including Guillaume Brouscon’s,) show a great big landmass almost exactly where Australia actually is, a good 50 or 60 years before the first documented European sighting. (By Dutch navigator Willem Janszoon, in 1606.)

800px-Australia_discoveries_by_Europeans_before_1813_enThere’s this funny gap in human knowledge of Australia. 50,000 years ago, humans equipped with little more than sharp rocks and pointy sticks managed to get to Australia and make themselves home. Then, for the next 49,500 or so years, everyone else forgot that it was there. (Aside from a few lost souls from India who washed up, IIRC, abut 10,000 years ago.) (It looks like the southern coast of Australia wasn’t even explored [by sea,] until 1801.)

Even China, an organized polity with excellent record-keeping, ship-making, and map-making skills going back centuries, does not show Australia on its maps (at least not on any map I’ve found,) until 1602.

1602 is still before 1606, but we will discuss these Chinese maps in a minute.

Portugal had a policy, in the 1500s, of treating its nautical maps as official state secrets. French spies, therefore, went and bribed Portuguese map-makers into sharing their secrets, the results of which are probably the Dieppe maps, due to their many Portuguese and French labels, indicating French cartographers working off Portuguese originals.

All of which raises the question of WHO was exploring Australia in the early 1500s. Was it the Portuguese? If so, they’ve done an excellent job (a few bribed cartographers aside,) in keeping it secret. Unlike the fabled Viking settlement in Vinland, we have yet to discover any hard evidence, such as Portuguese DNA or artifacts in Australia, that would confirm an early Portuguese presence.

The “Australia” landmass on the Dieppe maps is labeled “Jave la Grande.” Wikipedia claims that this name comes from Marco Polo:

“As explained by Sir Henry Yule, the editor of an English edition of Marco Polo’s travels: “Some geographers of the 16th century, following the old editions which carried the travellers south-east of Java to the land of Boeach (or Locac), introduced in their maps a continent in that situation”.[3]”

Behaim's Erdapfel globe, 1492
Behaim’s Erdapfel globe, 1492

The problem with this explanation is that in the two and a half centuries of map-making between the publication of Marco Polo’s adventures and the drawing of the Dieppe maps, no one stuck in a giant continental blob of land south of Indonesia, labeled “Jave la Grande” nor anything else. Jave la Grand does show up on some of these maps, but as a quite ordinary island about where you’d expect it. EG, the Erdapfel globe of 1492 (too early to include Columbus’s discoveries, which weren’t known until 1493, but definitely disproving the idea that people in Columbus’s day thought the world was flat.)

I find it highly unlikely that the Dieppe cartographers suddenly decided to turn “Jave la Grande” into a great big landmass in a spot where no prior European maps had ever shown land, and happened, totally by accident, to position it where there actually is a continent.

The Erdpafel's depiction of the Pacific, including Java Major
The Erdpafel’s depiction of the Pacific, including Java Major (aka Java la Grande)

It seems far more likely that they were working off charts that happened to show a large landmass in this spot, and needing a name for it, they chose the closest thing they could find in Marco Polo’s account. (I would not worry about the location being slightly off, due to these maps predating our ability to find longitude at sea by over a hundred years.)

That leaves the question of how Australia got on the charts. Just as the French got their information from the Portuguese, the Portuguese may have gotten their information, in turn, from someone else, like the Chinese, Indonesians, or Islamic mariners.

The Wikipedia page on Islamic geography is inadequate for me to draw any conclusions from it.

Japanese copy of Matteo Ricci's Kunyu Wanguo Quantu world map
Japanese copy of Matteo Ricci’s Kunyu Wanguo Quantu world map

As I mentioned earlier, the first Chinese maps (that I know of) to show Australia are from 1602, after the Dieppe maps. The Kunyu Wanguo Quantu were created by Matteo Ricci, an Italian Jesuit missionary. The Kunyu Wanguo Quantu combines, for the first time, the geographic knowledge of Europe and China.

Sancai Tuhui World Map
Sancai Tuhui World Map, the Shanhai Yudi Quantu, of 1609

Ricci got to China by hopping aboard a Portuguese vessel, which dropped him off at their colony in Goa. From there he traveled to Macau, and then to Beijing and the Forbidden City (though he never met the Emperor.) So I think it highly likely that Ricci had access to (or knowledge of) Portuguese maps/discoveries, or the Dieppe maps themselves. I suspect that Ricci’s knowledge of Australia did not come from Chinese sources, because the Chinese world map Shanhai Yudi Quantu, (1609,) though inspired by Ricci’s work, does not show Australia.

The Indonesians are another potential source. I don’t know anything about the history of Indonesian map-making, but the Wikipedia page on the prehistory of Australia intriguingly informs us:

…the people living along the northern coastline of Australia, in the Kimberley, Arnhem Land, Gulf of Carpentaria and Cape York had encounters with various visitors for many thousands of years. People and traded goods moved freely between Australia and New Guinea up to and even after the eventual flooding of the land bridge by rising sea levels …

Indonesian “Bajau” fishermen from the Spice Islands (e.g. Banda) have fished off the coast of Australia for hundreds of years. Macassan traders from Sulawesi regularly visited the coast of northern Australia to fish for trepang, an edible sea cucumber to trade with the Chinese since at least the early 18th century. Tamil sea-farers also had knowledge of Australia and Polynesia before European contact.[37] …

The myths of the people of Arnhem Land have preserved accounts of the trepang-catching, rice-growing Baijini people, who, according to the myths, were in Australia in the earliest times, before the Macassans. …

In 1944, a small number of copper coins with Arabic inscriptions were discovered on a beach in Jensen Bay on Marchinbar Island, part of the Wessel Islands of the Northern Territory. These coins were later identified as from the Kilwa Sultanate of east Africa. Only one such coin had ever previously been found outside east Africa (unearthed during an excavation in Oman).

Ruysch Map
Ruysch Map

So it is possible that the accounts of any of these folks could have made it onto local maps, and made their way from there to the Portuguese and the Dieppe maps (though I will note that if the Macassans got there in the 18th century, that is after the Dieppe maps, but I don’t know how exact that date is.)

There is, however, a potentially more mundane explanation for this odd landmass: it could just be South America. To European mapmakers of the late 14 and early 1500s, it was not at all clear that Columbus had discovered the edge of a new continent, rather than some islands off the coast of Asia–hence Ruysch’s 1507 map that show Massachusetts merging into China.

Mercator map of 1595 showing Hy-Brasil and an extra Iceland
Mercator map of 1595 showing Hy-Brasil and an extra Iceland

In the days before mariners could easily check their longitude at sea, the location of various islands could only be estimated by calculating the direction and speed the ship that had reached them had been going, eg, “Three days’ sail to the West.” This meant that islands could appear in different spots on different maps, which sometimes resulted in islands getting duplicated in maps created by compiling several earlier charts. Iceland, for example, shows up twice on this map:

I think it possible, therefore, that the Dieppe map makers had before them one map which showed the coast of Brazil as an island near Indonesia, and a second map showed it as part of a continent in between Europe and Asia, and simply recorded both on their combined map. Personally, I think the shape of Jave la Grande looks more like South America than Australia, but perhaps if I could read thee maps or examine them in more detail, I would revise that assessment.

Beatus T-O style Map showing the antipodes, 1050
Beatus T-O style Map showing the antipodes on the far right, AD 1050

This would be a case of the Dieppe map makers getting lucky, not unheard of phenomenon. Medieval Europeans believed, for example, in a mythical “fourth continent” located on the other side of the world, called fanciful names like “the antipodes” (“the backwards feet,” a reference to the amusing idea that people on the other side of the world are standing upside down relative to oneself–again, proof that Europeans well before Columbus knew the Earth is round;) or less fancifully, “terra australis,” “southern land.” Since the Bible commands Christ’s disciples to spread his Gospel to “the four corners of the Earth,” Medieval mapmakers, faced with only 3 continents, figured there had to be a fourth. But since philosophical opinions conflicted regarding this fourth continent, it was not always included on maps.

The European age of exploration pushed the borders of this fourth continent increasingly southward, as the vast expanse of the Pacific, Indian, and Atlantic oceans were found not to harbor it, until it was restricted to the area south of South America. But here folks got lucky, and spotted an actual continent right where their maps said there ought to be one. Likewise, when Australia first showed up on European maps, it was supposed to be a northern promontory of this most southerly land, and so depicted. Thus the name “Terra Australis” came to be inscribed on this territory.

So we are still left with a mystery: did someone actually map Australia before the Dutch, or did the Dieppe map makers just get lucky?

 

Maps Maps Maps: A short history (pt 1/2)

Mercator map of 1595 showing Hy-Brasil and an extra Iceland
Mercator map of 1595 showing Hy-Brasil and an extra Iceland

Old maps are full of curiosities, like completely mythical islands (eg, Hy-Brasil,) land masses radically out of place or duplicated, and massive changes in scale from one side to the other.

Historical map-makers had three main problems: 1. They couldn’t measure longitude, 2. Their maps were often based on compilations of lots of maps from many different sources, often resulting in confusion, and 3. Some groups were more wiling to share their maps than others. (For example, there are lots of questions about what exactly the Portuguese knew in the 14 and 1500s, like rumors that Portuguese fishermen were secretly hauling in cod off the coast of Massachusetts–more on the Portuguese later.)

c5933People generally made good maps of their local areas fairly early on–the Chinese have some excellent early early maps, for example. But beyond the immediate and local, maps quickly became less detailed and more stylized, as in this “T-O” style medieval map, which obviously is not even trying to be accurate, but to express a theologic point.

Since early sailors did not usually strike out over long stretches of open water, but headed to nearby ports or islands a few days’ sail away, I suspect that most early sea charts put a great deal of effort into describing the relevant rocky shoals to avoid and safe harbors to take advantage of, and not so much effort into describing the broad curve of continental coastlines.

While latitude can be fairly easily measured by simply measuring the height of the North Star in degrees (if you are at the equator, the North Star will lie on the horizon; if you are at 45 degrees north, the North Star will be 45 degrees high in the sky;  if you are at the North Pole, the North Star will be directly above you, or 90 degrees. If you can’t find the North Star, you’re south of the equator.) (Wyrd Smythe explains in more detail if you are confused.)

But there is no easy, low-tech way to determine longitude, your east-west position on the Earth’s surface. Longitude is not a huge deal when island-hopping short distances, but it becomes a huge deal once you’re undertaking multi-week trans-Atlantic or trans-Pacific voyages, where a storm can suddenly blow you days off course and you end up crashing into rocks you didn’t know were there. For example, in 1707, four British Navy warships were pushed off course by storms off the coast of England and crashed into the Isles of Scilly. 1,550 sailors drowned, prompting the British government to offer a 20,000 pound prize for anyone who could figure out a way to accurately determine longitude at sea.

recreation of Ptolemy's world map
Recreation of Ptolemy’s world map

The lack of knowledge and inability to make good measurements rendered even the best early maps of the world objectively terrible.

Here we have a reconstruction of Ptolemey’s world map, based on the geographical knowledge of AD 150, and Al Idrisi’s map drawn for Roger II of Sicily in 1154. Idrisi did a good job depicting Sicily, but nearby Italy is a complete mess, and he duplicates Ptolemy’s mistake of essentially depicting India as a big island (actually, probably confusion between the size of India vs. the size of Sri Lanka,) and Ptolemy’s complete confusion about the angle of Africa’s east coast.

Tabula Rogeriana, created by Al-Idrisi
Tabula Rogeriana, created by Al-Idrisi

Al Idrisi did know about the Pacific ocean and the east Coast of China, which Ptolemy did not, but his geography of Denmark and Britain are worse than Ptolemy’s, despite having been based in Europe while working.The lack of advancement in geographic knowledge available in the Mediterranean over 1,000 years is striking (though I would not be surprised to find out that folks were working with much better maps of local currents and shoals in their areas than their ancestors had been using in Ptolemy’s time.)

Gangnido map
Gangnido map

On the other side of the world, Chinese and Korean maps show a similar pattern. The Gangnido (aka Kangnido,) map of 1402, created in Korea, shows Korea, China, the Arabian Peninsula, and Africa. I think India is very slightly projecting from the lower-left side of the China blob, with Sri Lanka a bit more properly sized than on Ptolemy’s map.

The Gangnido map is based on an earlier Chinese map, the Da Ming Hun Yi Tu of 1398, which is very similar, but might have the Malay Peninsula.

Now, you might be thinking, as I did, that “Africa” and “Arabia” look a lot like India on this map. Wikipedia assures us that they aren’t and offers this explanation, especially since it is difficult for us non-Koreans to read the map: 300px-KangnidoPoliticalDetails

But the total lack of a Malay peninsula is really confusing, as I assume anyone traveling from China to India would be quite are of this enormous detour in their way. It’s like drawing a map of Europe and leaving off Spain.

These maps show the difficulties of trying to compile one map out of many, as your maps may use vastly different scales. The Gangnido and Da Ming Hun Yi Tu maps combine information compiled from Chinese, Korean, Japanese, Mongolian (the Mongol empire collected maps from all of its conquered nations,) and Islamic sources, eg, the voyages of Ibn Battuta.

I have noticed that no matter which explorer of south Asia we are talking about, whether Ibn Battuta, Marco Polo, Zheng He, or the Polynesians, none of them seem to have made it to Australia.

Neither do any of these early (1400s or before) maps seem to show Australia–in other words, the Chinese (and Koreans) were drawing recognizable maps of Africa and Europe before Australia.

Guillaume Brouscon world map, 1543
Guillaume Brouscon world map, 1543

European portolan charts appeared, seemingly ex nihilo, in the 13th century. The portolans used compass directions plus sailing directions to estimate distances between map points, thus producing a revolution in map accuracy. The compass roses are drawn directly onto the map for navigational convenience, as on this “Dieppe map” by Guillaume Brouscon, 1543.

It is getting late, so I am going to have to continue this on Thursday, when we will discuss the Dieppe maps in some depth. But let me know if you catch the most curious thing about them. ;)

 

 

The big six civilizations (part 5: China, Treasure Ships, and Eunuchs)

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I doubt I need to tell you that China was one of the first six major, basically independent civilizations to emerge in world history, but it was surprisingly late compared to the others.

Anyway, this post is going to only briefly look at the Erlitou, as I assume you are already fairly familiar with Chinese culture, and instead focus on the voyages of the Treasure Ships. And eunuchs.

The Erlitou culture appeared on the Li river around 1900 BC. The largest city, also called Erlitou, may have been home to 18,000-30,000 people, before the capital got moved and most of the folks moved away. They may have been the somewhat mythical Xia dynasty, but there isn’t enugh evidence, yet, to prove the association either way.

The Erlitou people had pottery, (and potters’ wheels,) could smelt bronze, were making silk, and raising domesticated plants and animals such as wheat, rice, millet, pigs, and goats. (Rice was originally domesticated in south Asia, but had spread by this point to China.) I believe they also had some form of proto-writing.

They weren’t the first folks in the area–they succeeded the Longshan culture, which had small farming villages and probably morphed into the Erlitou–but they appear to be the first large polity.

Now that’s all well and good, but the interesting stuff came later.

The many helpful comments back on my post, the Hikikomori Nations, pointed me to the naval journeys of Zheng He, who commanded the Chinese navy, battled pirates, and sailed to Indonesia, India, and Africa back in 1405-1433.

Then, almost as suddenly as these “Treasure Voyages” had begun, they ended. Wikipedia explains why:

The treasure voyages were commanded and overseen by the eunuch establishment whose political influence was heavily dependent on imperial favor. However, within Ming China’s imperial state system, the civil government were the primary political opponents of the eunuchs and the opposing faction against the expeditions. Around the end of the maritime voyages, the civil government gained the upper hand within the state bureaucracy, while the eunuchs gradually fell out of favor after the death of the Yongle Emperor.

This left me scratching my head. Eunuchs were a political block in early 15th century China?

The Wikipedia page on Eunuchs helpfully explains:

In China, castration included removal of the penis as well as the testicles. …

From ancient times until the Sui Dynasty, castration was both a traditional punishment … and a means of gaining employment in the Imperial service. Certain eunuchs gained immense power that occasionally superseded that of even the Grand Secretaries. Zheng He, who lived during the Ming Dynasty, is an example of such a eunuch. Self-castration was a common practice, although it was not always performed completely, which led to its being made illegal.

It is said that the justification for the employment of eunuchs as high-ranking civil servants was that, since they were incapable of having children, they would not be tempted to seize power and start a dynasty.

*Mind boggles.*

Sun Yaoting, right, and his biographer, left
Sun Yaoting, right, and his biographer, left

The last Imperial eunuch, Sun Yaoting, died in December 1996.

Here’s an Australian article about poor Sun:

For centuries in China, the only men from outside the imperial family who were allowed into the Forbidden City’s private quarters were castrated ones. …

Sun’s impoverished family set him on this painful, risky path in hopes that he might one day be able to crush a bullying village landlord who stole their fields and burnt their house.

His desperate father performed the castration on the bed of their mud-walled home, with no anaesthetic and only oil-soaked paper as a bandage. A goose quill was inserted in Sun’s urethra to prevent it getting blocked as the wound healed.

He was unconscious for three days and could barely move for two months. When he finally rose from his bed, history played the first of a series of cruel tricks on him – he discovered the emperor he hoped to serve had abdicated several weeks earlier.

Sun was eight years old at the time.

The young ex-emperor was eventually allowed to stay in the palace and Sun had risen to become an attendant to the empress when the imperial family were unceremoniously booted out of the Forbidden City, ending centuries of tradition and Sun’s dreams.

“He was castrated, then the emperor abdicated. He made it into the Forbidden City then Pu Yi was evicted. He followed him north and then the puppet regime collapsed. He felt life had played a joke at his expense,” Jia said.

If you’re curious, Yinghua Jia wrote a whole book about Sun’s life, The Last Eunuch of China. (It has 4.5 stars.)

You know, growing up, I heard fairly frequently about Chinese foot-binding (done to women) and harems (in various countries.) There was a fairly frequent intellectual subcurrent of “historical cultures were mean to women.” NO ONE EVER MENTIONED THE EUNUCHS.

Okay, carrying on: so there were apparently enough men whose parents had thought it a good idea to lop of their genitals in order to get them a job that they constituted an opinion-making polity within the Chinese government, and got into conflicts with the Confucian scholars, who I assume hadn’t been horrifically mutilated by their parents.

The Treasure Voyages were thought up by the Eunuchs, and the admiral of the Treasure Fleet, Zheng He, was a eunuch:

Zheng He (1371–1433 or 1435), often spelled Cheng Ho in English, was a Hui court eunuch, mariner, explorer, diplomat, and fleet admiral during China‘s early Ming dynasty. Born Ma He, Zheng commanded expeditionary voyages to Southeast Asia, South Asia, Western Asia, and East Africa from 1405 to 1433. …

As a favorite of the Yongle Emperor, whose usurpation he assisted, he rose to the top of the imperial hierarchy and served as commander of the southern capital Nanjing (the capital was later moved to Beijing by the Yongle Emperor). …

Zheng He was born into a Muslim family.[7][10][11]

He was a great-great-great-grandson of Sayyid Ajjal Shams al-Din Omar, a Persian who served in the administration of the Mongol Empire and was the governor of Yunnan during the early Yuan dynasty.[14][15] His great-grandfather was named Bayan and may have been stationed at a Mongol garrison in Yunnan.[7] His grandfather carried the title hajji.[1][16] His father had the surname Ma and the title hajji.[1][7][16] The title suggests that they had made the pilgrimage to Mecca.[1][7][16] It also suggests that Zheng He may have had Mongol and Arab ancestry and that he could speak Arabic.[17]

Zheng He had a distinguished career in the army before becoming head of the Chinese navy.

It is generally accepted (based on Ming dynasty records) that Zheng He died in 1433 at Calicut in India during the return leg of the seventh voyage and was buried in Calicut or at sea,[48] although some theories, based on artifacts associated with him and believed to be from later than 1433, posit that he died shortly after that voyage in 1434[48] or early 1435.[49]

A tomb was built for Zheng He in Nanjing. This is usually believed to be a cenotaph containing his clothes and headgear as his body was buried at sea or in Calicut, but other theories exist as to whether Zheng He was buried in Nanjing, and if so, where. In 1985, a Muslim-style tomb was built on the site of the earlier horseshoe-shape grave.[50] He adopted the eldest son of his elder brother, who was awarded a hereditary officer rank in the imperial guard.

The voyages of Zheng He
The voyages of Zheng He

As for the Treasure Fleet itself:

The grand project resulted in seven far-reaching ocean voyages to the coastal territories and islands in and around the South China Sea, the Indian Ocean, and beyond. … The first three voyages reached up to Calicut on India’s southwestern coast, while the fourth voyage went as far as Hormuz in the Persian Gulf. Afterwards, the fleet made voyages farther away to the Arabian Peninsula and East Africa.

While the voyages did result in better maps, they weren’t exploratory, like Columbus’s–the Chinese were already well aware that India and Africa existed before they set out:

Chinese seafaring merchants and diplomats of the medieval Tang Dynasty (618—907) and Song Dynasty (960—1279) often sailed into the Indian Ocean after visiting ports in South East Asia. Chinese sailors would travel to Malaya, India, Sri Lanka, into the Persian Gulf and up the Euphrates River in modern-day Iraq, to the Arabian peninsula and into the Red Sea, stopping to trade goods in Ethiopia and Egypt (as Chinese porcelain was highly valued in old Fustat, Cairo).[11] Jia Dan wrote Route between Guangzhou and the Barbarian Sea during the late 8th century that documented foreign communications, the book was lost, but the Xin Tangshu retained some of his passages about the three sea-routes linking China to East Africa.[12] Jia Dan also wrote about tall lighthouse minarets in the Persian Gulf, which were confirmed a century later by Ali al-Masudi and al-Muqaddasi.[13] Beyond the initial work of Jia Dan, other Chinese writers accurately described Africa from the 9th century onwards; For example, Duan Chengshi wrote in 863 of the slave trade, ivory trade, and ambergris trade of Berbera, Somalia.[14] Seaports in China such as Guangzhou and Quanzhou – the most cosmopolitan urban centers in the medieval world – hosted thousands of foreign travelers and permanent settlers. Chinese junk ships were even described by the Moroccan geographer Al-Idrisi in his Geography of 1154, along with the usual goods they traded and carried aboard their vessels.[15]

Giraffe brought back on one of Zheng He's voyages, a gift to the Emperor from Somalia
Giraffe brought back on one of Zheng He’s voyages, a gift to the Emperor from Somalia

Nor was trade the main point, because Chinese merchants were already doing plenty of trade. Rather:

The Chinese expeditionary fleet was heavily militarized and carried great amounts of treasures, which served to project Chinese power and wealth to the known world. They brought back many foreign ambassadors whose kings and rulers were willing to declare themselves tributaries of China. During the course of the voyages, they destroyed Chen Zuyi‘s pirate fleet at Palembang, conquered the Sinhalese Kotte kingdom of King Alekeshvara, and defeated the forces of the Semudera pretender Sekandar in northern Sumatra.

There is some debate about exactly how big the Treasure Ships were, but the general consensus appears to be that they were some of (if not the) biggest in the world at the time, and carried about 27,000 people. (Total, not per boat.)

Due to bad record keeping (more on this later,) there is some debate (or spirited fantasy) about where, exactly, Zheng He (and other Chinese admirals) sailed:

He is best known for his controversial book 1421: The Year China Discovered the World, in which he asserts that the fleets of Chinese Admiral Zheng He visited the Americas prior to European explorer Christopher Columbus in 1492, and that the same fleet circumnavigated the globe a century before the expedition of Ferdinand Magellan. …

Menzies states in the introduction that the book is an attempt to answer the question:

On some early European world maps, it appears that someone had charted and surveyed lands supposedly unknown to the Europeans. Who could have charted and surveyed these lands before they were ‘discovered’?

In the book, Menzies concludes that only China had the time, money, manpower and leadership to send such expeditions and then sets out to prove that the Chinese visited lands unknown in either China or Europe. He claims that from 1421 to 1423, during the Ming dynasty of China under the Yongle Emperor, the fleets of Admiral Zheng He, commanded by the captains Zhou Wen, Zhou Man, Yang Qing, and Hong Bao, discovered Australia, New Zealand, the Americas, Antarctica, and the Northeast Passage; circumnavigated Greenland, tried to reach the North and South Poles, and circumnavigated the world before Ferdinand Magellan.

Unfortunately, it looks like Menzies massively over-reached and doesn’t provide much proof, as many of his reviewers point out.

Our original question that started this whole quest was whether the Chinese discovered Australia (or New Zealand) before the Europeans. (And not Taiwanese-descended Polynesians, who obviously got to NZ first.)

According to Mega-Tsunamis, Chinese Junks, and Port Philip Bay (a very speculative article linked in the comments on the original post):

In 1450 AD, the catastrophic comet Mahuika descended upon the coast of New Zealand. Reputed to be twenty-six times as bright as the Sun, it discharged electrically and shattered Admiral Zhou Man’s Chinese fleet of some sixty ships. The fleet supported a thriving Chinese colony of Han, Tang and Song, mining gold, jade and antimony in New Zealand. The comet’s screaming noise blew out the sailors’ eardrums; they received horrific burns. …

These facts are recorded in the meticulous fifteenth century records of Chinese ambassador Zheng He. Historian Gavin Menzies claims that over nine hundred ships failed to return to China from Pacific expeditions in that tragic year.

I don’t know how much of this comes directly from Menzies’ work vs. other peoples’ speculations, but since Zheng He died in 1433 (or maybe 1435, at the latest,) I don’t think he was writing very much about comets in 1450. Further, I find it unlikely that Admiral Zhou Man was commanding a fleet of Chinese ships in 1450, given that the last Treasure Voyages ended in 1433, after which official Chinese sentiment turned against the voyages and the ships were left to rot in their docks. Wikipedia notes:

In the Ming court, the civil officials were the faction who were against the voyages.[143][156][168] In contrast, the eunuch establishment stood at the head of the fleet and the expeditions.[140][141][156][168] The civil officials condemned the expeditions as extravagant and wasteful.[168][169] Traditionally, they were political opponents of the eunuch establishment,[140][156][168] but also to the military establishments who crewed the fleet.[156] … On cultural grounds, the hostility came forth due to the trade and acquisition of strange foreign goods which stood in contrast to their Confucian ideologies.[171][172][168][169] The undertaking of these expeditions only remained possible as long as the eunuchs maintained imperial favor.[141][173]

The Hongxi Emperor was fiercely against the treasure voyages throughout his reign.[80] After the advice of Xia Yuanji, he ordered the cessation of the treasure voyages on 7 September 1424, the day of his accession to the throne.[93]

After 1433, the civil officials succeeded in halting subsequent maritime expeditions.[170] The ships were left to rot, while their lumber was sold for fuel in Nanjing.[170] The mariners were reassigned to load grain on barges of the Grand Canal and to build the emperor’s mausoleum.[170] After the voyages, subsequent Ming emperors would reject the Yongle Emperor’s policy of bringing the maritime trade into the structure of the tributary system.[140]

It also looks like there was some effort to suppress or destroy records of the voyages, (leaving ample room for folks like Menzies to speculate on what might be missing,) so that future leaders wouldn’t get the wrong idea and try to recreate them.

Further:

From 1405 to 1433, large fleets commanded by Admiral Zheng He—under the auspices of the Yongle Emperor of the Ming Dynastytraveled to the Indian Ocean seven times. This attempt did not lead China to global expansion, as the Confucian bureaucracy under the next emperor reversed the policy of open exploration and by 1500, it became a capital offence to build a seagoing junk with more than two masts.[16] Chinese merchants became content trading with already existing tributary states nearby and abroad. To them, traveling far east into the Pacific Ocean represented entering a broad wasteland of water with uncertain benefits of trade.

While trade continued, official support and imperial navies did not, largely justified by the Haijin doctrine, which banned maritime shipping in 1371 and enforced to varying degrees over the years:

In the second month of the first year (1661) of Kangxi, the Qing court issued an imperial decree: The sea shore inhabitants will be ordered to move inland 50 li, to curb their links with the Taiwan rebels under Koxinga. Soldiers then moved in and set up the boundary: in just three days, all houses were razed to the ground and all inhabitants evacuated. … Warnings were placed on notice boards stating that “Anyone who dares to step over the border line shall be beheaded!” “Persons found a few paces over the border line, shall be beheaded instantly.”

This is, however, well after the time period we are discussing. It looks like the main reason the Treasure Voyages were canceled (aside from eunuchs vs. Confucian conflicts) is that the Mongols became a problem (the Mongols were frequently a problem, after all,) and China had to devote its energies to defending its land borders rather than sailing about the ocean.

Perhaps the best evidence either way would be maps:

Gangnido map
Gangnido map
Selden Map
Selden Map
page from the Mao Kun map, showing the South China Sea with Paracel and Spratly Islands
A page from the Mao Kun map, showing the South China Sea with Paracel and Spratly Islands

These are the maps I’ve found so far, none of which show Australia or New Zealand. The Mao Kun map is supposed to be based of Zheng He’s maps, and is divided into 40 pages, showing the coasts of China, India, east Africa, etc.

The Seldon Map, from the early 1600s, while very good, does not show Australia, and the Gangnido map (and its later, updated copies,) which people think may show the Arabian peninsula, Africa, the Mediterranean, and part of Europe on its left side, (but strangely, the Malay Peninsula and India were smooshed together into the left-hand side of the big China blob, according to the Wikipedia talk page.)

At any rate, it looks like Australia and New Zealand didn’t make it onto the maps until much later–if they were known to the Chinese, they were probably regarded as unimportant due to lack of valuable trade goods or political states to trade ambassadors with.

I find the difference between the official Chinese reaction to the Treasure Voyages and the European reaction to Columbus’s discoveries remarkable.