The notion of Terra Australis Incognita — the Great or Unknown Southern Land — came about in the fourth century BCE.
Greek philosopher Aristotle thought a great land mass must exist south of the equator to balance the weight of the lands in the north:
"...there must be a region bearing the same relation to the southern pole as the place we live in bears to our pole..."
Although the idea of a vast southern continent always had its followers and detractors, it was largely discounted during the Middle Ages before once again gaining favour in the 15th century.
It was a time of expanding global exploration and long maritime voyages. Growing numbers of European explorers set out to map uncharted oceans and lands drawing on the work of the world’s earliest and greatest cartographers Claudius Ptolemy (c100CE-c170CE).
Ptolemy’s maps — rediscovered after more than 1000 years — showed a southern land mass that counterposed the northern continents.
This land mass was thought to centre on the South Pole and cover the entire southern end of the globe, up to about latitude 60° S.
Many explorers sighted and began to map the southern lands and, at various times, Australia, New Zealand and Papua New Guinea were each proposed to be part of Terra Australis.
By 1768, when the HMB Endeavour set sail these theories were in doubt.
Searching for Terra Australis
After observing the Transit of Venus in Tahiti, Captain James Cook opened a set of secret orders from the British Admiralty. In those orders, Cook was tasked with trying to find Terra Australis and to lay claim to it on behalf of the British Monarch.
His instructions were to look for the Southern Continent in the South Pacific Ocean. He was to move south to latitude 40° from the previous search coordinates, then head west until he reached New Zealand at latitude 35°. If he could not find a land mass, he was directed to further explore New Zealand.
Having failed to find a new continent east of New Zealand, Cook thought he had made no great discoveries.
After charting New Zealand he progressed on to Australia well aware it was already known to the Dutch as New Holland.
By mapping the east coast, Cook confirmed New Holland was not part of the great Terra Australis, nor did it connect to New Guinea — although Cook felt he was just clarifying what was already suspected.
As per his orders, Cook claimed British possession of the east coast of Australia and called it New South Wales. The continent was then known by two names — New Holland in the west and New South Wales in the east.
The land beyond the ice
On his second voyage, Cook set out even further south to continue the search for Terra Australis. He saw and was thwarted by solid sea ice, which he proposed surrounded a polar continent, but he never saw the land he had long sought.
It was not until 1820 that Antarctica was discovered and another southern land was confirmed. It was not the vast, habitable, land mass that had been imagined for close to two millennia and the existence of a great Terra Australis Incognita was finally put to rest.
By that time explorer Matthew Flinders (1774-1814) had mapped the Great Southern Land and named it ‘Australia’.
Naming the Great Southern Land
In 1803, Flinders became the first British person to circumnavigate the continent accompanied by Aboriginal explorer Bungaree, a Kuringgai man who provided guidance and interpretation during the voyage.
Flinders said that to extend either ‘New Holland’ or ‘New South Wales’ to cover the entire land mass would be a disservice to either the Dutch or the British. His proposition was to find a general name for the whole continent and he initially favoured a return to Terra Australis, which it was believed to have been a part of for so long.
In 1804, Flinders wrote both Terra Australis and Australia on his hand drawn map of the continent which accompanied his book A voyage to Terra Australis.
Publication of the book and chart were delayed until 1814 and, for a time, both Terra Australis and Australia were used to refer to the Great Southern Land. But, by the end of the 1820s, ‘Australia’ was more commonly used as the continent’s name.