I didn't mean ancients and Australia, but rather the early European discoveries in the 17th century. It wasn't really until British colonisation that Australia became generally accepted as a continent in its own right, separate from Asia.
To be perfectly honest, the only occurence of an identification with Asia I can think of is the
Grande Jave (Great Java) of french geographers in the XVIIth century, which had little posterity and badly identifiable with Australia.
What I tought was more common was the identification with a fantasmed
Terra Australis, a continent that supposedly covered the southern part of Earth to balance the Pacific sea.
Can I ask where you found about these identification with Asia? Looks interesting.
Interesting, so the people of the Levant also had the concept of the three continent system?
Probably less continent as we concieve them than main landmasses and more preciselty their coasts.
For long, you had discussion about Africa, not unlike you had far more recently with Europe : was it an Asioafrican landmass or not?
Not that the same distinctions were used, of course : Nile river was widely used as the border between Asia and Africa, for instance (now, you had critics of this concept even then, as Herodotus calling everyone idiot)
I was wondering if it'd be possible to have more 'cultural continents' like Europe, with shared characteristics - India, the Middle East, the Sinosphere etc.
I don't think so : it required a far more important knowledge of the region that was avaible then, in Antiquity or Christian Middle Ages.
After all "Europe" is essentially a social construction from Europeans : why bother at whatever weird concept foreigners we barely knew that they exist? (I'm exagerating a bit, of course, all continent is at least partially a social construct, but it's clearly obvious with Europe, rather than being even less of a continent)
Arabo-Islamic civilisation had probably the most chances to see a more sub-continental approach, that said.
But even there, the bad geographical knowledge of Africa and Far East is a problem : takes the wonder of medieval carthography that is the
Tabula Rogeriana. It's damn good for mediterranean basin (you'd notice the über-Arabia, which certainly have nothing to do with cultural bias; not unlike Europe on XVIIIth/XIXth projections) but really less precise outside.
So, have a more knowledgable Arabo-Islamic carthography, with a distinction made for India, and you may end with more sub-continents, enough for that they are more widely used scientifically and culturally.