So if this is canon...

Freeza had a brother, or relative, named Chilled. Chilled discovered the Saiyajins, most importantly the existence of Super Saiyajins. On his death bed, he told his crew to warn his family of the Saiyajins, which caused Freeza to hunt them down and (ultimately) exterminate them. This culminated in sending Bardock back in time, where he became a Super Saiyajin and defeated Chilled, repeating the cycle.

So how does the initial timeline go? In every scenario, in order to get to the point where Bardock "dies" at Freeza's hands, Freeza has to be aware of, and afraid of, the Saiyajins because of what he heard from Chilled. But this only happened because Bardock was sent back in time by Freeza's energy explosion, causing Chilled to have his fateful clash. There has to be that first timeline somewhere that created the loop. But how?

My brain hurts from thinking about this....