Bartok is an important person in Saiyjin history. He was a moderate fighter but a brilaint scientist. In fact it was Bartok who invented the artificial moon light so a Saiyjin could transform on a planet with no moon. He also led all the Saiyjins along with hundreds of other people in a revolution against Freeza. They fought long and hard, but it was in vain. And when it became clear that they weren't going to win, Freeza offered him a chance to live. His reply was "I'd rather be a free man in my grave, then serve you another day!" And with that the saiyjins were distroied.
Bartok had two sons. The first he named Raddiz and was rather impressed that he was a first class worrier, since he himself was only third class. He predicted his next son would be one of the strongest worriers in Saiyjin history, so he was disapionted when Kakerott was born a third class Saiyjin. But he didn't lose hope, he sent his son off to destroy a planet called Earth (thinking it would raise his power level)