It's a slow afternoon, and Alcxxk's panblocker thread is still clogging the U-bend, so I've been looking up swearwords. From the OED:

'The word "bugger" entered Middle English in the sense of 'heretic', from the Old French word "bougre". It was used of members of a heretical Christian sect based in Albi in southern France in the 12th and 13th centuries (the Albigensians). The word ultimately comes from the Latin "Bulgarus", meaning Bulgarian: Bulgarians belonging to the Orthodox Church were regarded as heretical by Roman Catholics. The sexual meaning of the term arose in the 16th century from an association of heresy with forbidden sexual practices.'