Bogomil was a 10th Century Bulgarian priest. And a heretic - in a time when being heretical was often a better route to fame than being really orthodox.
Their heterodoxy was belief in creation by an
evil anti-god - ie the devil. But
I suspect a larger problem of heresy may have been their
rejection of the church hierarchy, which could have been more
anathematic than
religious heterodoxy. This seems to have emerged at a time of
increasing stratification of their society, which encompassed enserfdom
and alienation of church ritual. They were gnostic, which encompassed both the anti-god and anti-establishment hazards - and were counted as spiritual ancestors of the French Cathars, against whom the pope decreed a crusade - which contributed to the wiping out of gnosticism in Europe.
The church also propagated some nasty rumours against the Bogomils, including that they were sodomites. In France, Bogomils were seen as equivalent to Bulgarians, known as "Bougres". From this comes the English word bugger.
