From Dragon Eye Atlas
Following the Epoch of Destruction, the lands of Auseka were changed - and empty. The death toll and the fall of the centaurs had left spaces for other races to fill them, and humans were chief among those who took the opportunity. The Age of Man had begun.
There were human tribes before this time, living in the most primitive of conditions, hunting with stone weapons and living in caves or primitive huds of sticks, leaves, mud and fur. But when the dust settled and both the elves and dwarves had been reduced in numbers, or retreated from many parts of the world, humans began to multiply and expand, and possibly discovered settlements and tools of the older races.
From about 2,500 years ago we have the first evidence of humans using metal tools, farming the land and domesticating animals. They may have started earlier, but records are unreliable. In maybe a thousand years humans expanded to all corners of the world and advanced in technology towards first copper, then iron smelting. They started to build houses from wood, and fortified their villages. Slowly, they began to be masters of the natural environment they found themselves in, and tribes evolved into villages and then into alliances and proto-realms.
Very little is known about the details of this age. The dwarven and elven scholars have few records on early humans, as they did not consider them important. There may have been trade between humans and the older races, though it is not clear what humans would have to offer at this stage of their development.
What little tales exist among the elves and dwarves describes early humanity as savages banging rocks together, dying young and breeding fast. It is not clear if especially the elves, who still dwelled above ground, overlooked the young race or dismissed them.