Sorry, I meant civilisation.
Depending if you delve into fantasy or not, you can evoke the power of author's license and make civilisation as old as you like...what period of history are they in? How advanced is the world?
Decide the metal composition of the world, so as to mark the places that would have gained abilities with bronze and iron first, and from there, depending on how old the world is and how much one country could affect another, decide how old human civilisation is...if it's old enough, you could end up with some very interesting political structures. Remember the younger the world is, the less it has been explored...