Goku's father.  He along with his friends was sent by Frieza to destroy a planet.  They had wiped out the entire population, but the last of the race put a curse on him so that he could see the doomed future of his planet and his people.  After Bardok recovers from his battle, he sees a vision of Frieza destroying the Planet Vegeta and the Saiyan race. Mean while, Kakarot (his newly born son) is sent in a space pod to earth for him to destroy it.  Bardok tries to warn his crew, but when he reaches them they had already been killed by Didoria and Frieza's men.  He then tries to warn the rest of his people, but they take it as a joke.  When Frieza and his henchmen attack, Bardok stands up to him and fires at him.  Frieza's fireball absorbs Bardok's blast.  He sees his son in the future facing off against Frieza and knows that he will beat him.  He smiles and says "my son lives on" and dies a happy death as the rest of his planet is destroyed.

It is often said that Bardok and his crew are average, low class Saiyans, but like Goku, they are exceptionally strong.  Because of this Frieza saw them as a threat which was why he had them destroyed.  Before his death Bardock was one of the strongest Saiyans alive, he was a great fighter which came as a great shock to Didoria who had expected him to be "nothing but a low class fighter".