The first part of a developing WU on Australia
The discovery of Australia
The first humans to discover the land that would later be called Australia came from the area that is presently south-east Asia between 100 000 and 60 000 years ago, travelling over land bridges exposed by the trapping of sea water in polar ice caps. It is thought they may also have employed rafts, and tests have shown that a journey from modern-day Indonesia to Australia would be almost impossible to get wrong. Settlement was fairly stable by 40 000 years ago, but contact with lands to the north continued, and about 3 500 years ago (contemporary with middle kingdom Egypt, Bronze Age Europe and the rise of civilisation in the Fertile Crescent) Asian seafarers introduced the dog to Australia. The dingo, as this species of dog is known, is the only land mammal apart from humans found in Australia before European settlement which is not either a marsupial, a monotreme, a rodent or a bat.
The Indian Ocean was known to the Roman empire, some of whose citizens traded on the south-west coast of India. But exploration of that ocean did not advance much until the great Chinese navigator, admiral Cheng-Ho (or Zheng He), whose seven great voyages lasted from 1405 to 1433. These voyages are thought by some to have involved sightings of the coasts of most of the continents, with the notable exceptions of Europe and Antarctica. Maps dating from before 1492 show reasonable approximations to the coasts of both North America and Australia, and most scholars consider it reasonable to assume that Cheng-Ho visited or at least sailed part way around Australia. The Chinese are known to have traded on Timor and New Guinea, and Australia is not far beyond, in terms of the distances covered by Cheng-Ho's vast treasure ships. One of these enormous vessels, the ocean liners of their day, is thought to lie at the bottom of the Carribbean Sea. If true, this would provide concrete evidence of the scale of the Chinese exploration. Unfortunately, an artefact said to be a Ming dynasty figurine, found near Darwin in 1879, is now thought to be nineteenth century. Despite this, Cheng-Ho's voyages remain a remarkable endeavour, and probably represent the first sighting of Australia by dedicated explorers.
Another group with a stake in the discovery of Australia are the Macassan people native to the islands of Malaysia. From about the mid seventeenth century, they seem to have been regular visitors to northern Australia, fishing for trepang, or beche-de-mer. This is borne out by archaeological evidence on the shores of the Gulf of Carpentaria and elsewhere, as well as by changes in (Australian) Aboriginal canoe design about this time to resemble the Macassan form. In all likelihood, the first dug-out canoes in Australia were traded to the inhabitants by the Macassans. It is thought that it was from this source that the Eurasian disease of smallpox reached Australia, because although it was known in the Dutch East Indies, the first case of smallpox in a white man in Australia was contracted from an Aboriginal. In all likelihood, the disease had been carried across the interior of the continent by Aboriginals, having been transmitted to them by infected Macassans on the north coast.
Source: Sir Geoffrey Badger: Explorers of Australia (2001). The forthcoming book 1421 has more details on Cheng-Ho, and when I get a copy, this node will be further updated.