From Bulgar(us, i), a reference to the Bogomils, a sect originating from Bulgaria, and condemned by Rome as heretic. It was probably hence accused of every sin
including sodomy, this as part of the propaganda involved for the Crusade against the Cathars (theologically directly related to the Bogomils). Remember the "Kill them all! God will sort them out..." ? This is the tragic epilogue of this Crusade.
The "Perfecti" among the Cathars were themselves accused of sodomy, and burnt as such. It was quicker an accsuation than to demonstrate heresy against these well-trained scholars. However, the monacal rules of the Perfecti included celibacy and abstinence; you're not recognized as a priest, but you don't touch women? This is against the holy laws of nature, ergo... the Inquisitor sues you for homosexuality.
Today, both Bogomilism and Catharism are considered as an early attempt to renew Christianity in its original form, which included a rejection of Roman church and its obscurantism. Hence, the Cathar areas of France were to become early supports of Protestantism.
Another explanation is that "sodomist" and "heretic" were equivalent crimes before the Inquisition. Hence, the amalgamation of both crimes, on behalf of the poor Bulgars.
Distorted by French to bougre (still used as an insult, usually mild as in "pauvre bougre" (poor chap), but sometimes worse), then by English in bugger.
Later, it may be noted that the same slander of sodomy and/or homosexuality was often used in the catholic crackdowns against Masonry...
Hence, this vile "bugger" is derived from a medieval libel, and is probably the oldest homophobic insult.
Thank you for your attention...
