In my world of Martapa it really depends on who you are on how important you come from is. For the common human peasant, you know who your grandfather's father was, but not much further back. For nobility, there are probably books and books full of your ancestors linking you all the way back to the time of Peter or earlier. Akicitia see knowing their family history as a mark of pride. Krom could mark his family back to the time of the Chosen, at the very least, making him a descendant of Mahatalo himself. A player needs decide if they want a long drawn out family tree or just one that can be traced back to grandpa. Give rewards to those who figure it out, either way, with a good reason for both. A Knight without a known history of family ties had better have a good reason, just as a peasant born character must have a good reason to know family ties back more then a dozen generations. Was the Knight raised for some deed he did the crown? Was the peasant descended from some High King's bastard and they were extremely proud of that fact? It all ties back to having a good background for your characters, because good backgrounds not only round out the character but give a good GM something to play with while planning out adventures.