you all seem to have chosen very hero-like names...
but...
i think in a midevil world most of the kids are beeing born from poor people, non-aristocratic simple farmer or servant\'s doughters and sons. in my imagination such people don\'t have real lastnames, maybe something like \'smith\' or \'hillfarmer\' would be possible but nothing that sounds like a long history of honor.
my char is the son of a vagabond and a bar-tender, his mother (working  in a bar) just called him TRUX because it\'s fast and easy to shout...his mother also cannot remember of having a lastname...

/actually TRUX was the name of the neighbour\'s dog in my childhood...