What the hey, why not.
In is as the Barkindji culture, located at the fork of the Murray and Darling rivers in Australia. Coloured
Dark Slate Gray.
More to come later, most likely.
I'm guessing it'll be more of a culture than an actual polity, and other NPC polities will spring up across habitable Australia as knowledge of domesticable macadamia- and wattle-farming grows.
Excerpt from the Encyclopaedia Antipodeia, the premier encyclopaedia on the Southern continent of the Antipodes.
Barkindji Confederacy
See also: Widiwiri, Macadamia Farming, Wattle Farming, Ngurendi-Menindi River Basin, Ngurendi-Menindi Culture
The Barkindji Confederacy was a culture of settled farmers who built Australia's first city in ~1600 BCE. The Barkindji are believed to be the first settled culture in the Antipodes, founding their city at the agricultural heartland of the continent at the confluence of the
Ngurendi and the
Menindi rivers.
Agriculture first became widespread on the Antipodeian continent in the 3000s BCE, with the various inhabitants of the fertile regions along the rivers discovering new methods to farm the
arletyeye plant†, which created a stable and plentiful non-migratory food source for the Ngurendi hunter-gatherers of the region. In time, the pseudo-settled hunter-gatherers also tamed the
boombera nut and the seeds of the
arlepe tree*, transitioning to a fully settled lifestyle of small villages in time. They lived off a staple diet of yams, supplemented by large amounts of boombera (which was ground up and mixed with water and native fruits into a kind of porridge),
bread made of milled arlepe seeds, and large amounts of meat (mostly kangaroo). Around 2600 BCE, the Ngurendi peoples began to discover metal working, moving from stone tools to tin and later bronze, which led to an increase in the size of the towns as new tools made construction, farming and hunting easier. These tools soon became weapons, as the various peoples of the region were forced to fight off predatory hunter-gatherer tribes from outside the river basin and, in time, each other. Trade along the basin grew, with with goods from one end of the river system being passed down and exchanged for shellfish and pearls from the coastline. Jewellrymaking, pottery, and the arts flourished.
Eventually, throughout the internecine warfare and politics between the villages of the river, one became much more powerful than the others. Based at the confluence of the two rivers, the village of Widiwiri benefited greatly from trade and it became extremely prosperous in comparison to its neighbours. Eventually, it managed to unite the Barkindji people into a sizeable confederacy, becoming the first proper state in the Antipodes. Ruled by a collection of tribal elders and armed with bronze weaponry, it became one of the most dominant powers in the region...
†Our point of divergence, ladies and gentlemen. Historically, Australia doesn't have much in the way of easily domesticable food crops that would facilitate settlement and urbanisation. The Vigna Lanceolata, or Pencil Yam, would have been a good contender, but only grows out in the middle of the desert where water is scarce and thus can't provide a stable food source. In this timeline, a variety evolves which thrives in wetter, better watered regions on the Murray-Darling rivers, thus creating a stable food source and allowing settlement.
*Both of these were eaten as part of the traditional Indigenous diet, however, on their own don't provide enough nutrition for settled living.