How did the word fuck?

There are several competing legends of origin of the most popular at present English swearing - the word fuck. The ban on its use was so severe that the first time the word appeared in the academic English Dictionary only in 1966. Academic version argues that the word fuck came into English from Dutch, German or one of the Swedish dialects in the XV century. In particular, the similar-sounding Dutch fokken translated as "pairing" (cattle), the word fokka on one of the Swedish dialects means "to copulate" and close to the Swedish word fock meaning penis. In literary English the word first appeared in the XVI century - in 1509 was published an anonymous satirical poem «Flen, Flyss», where the word is encrypted and, moreover, is disguised as a Latin - inscription gxddbov, quite suitable to the rhythm, which should read fuccant ( used letters, which in Old English version of the Latin alphabet were located behind a coded letters) - so would look like a verb fuck in the plural third person present, whether it is in Latin. The very phrase, written in a strange mixture of Latin and English, sounded like «Non sunt in celi quia fuccant uuiuys of heli», which translates roughly as "they will not be in heaven because they copulate with the wives of Ely". "They" - the monks from the monastery, situated in the town of Ely, a suburb of Cambridge. Other versions of origin of the word - they know, at least four, and they all declare fuck acronym - serious philologists believe unfounded. According to one of them, the word fuck stands for Found Under Carnal Knowledge, which can be translated roughly as "traces of carnal knowledge" - reducing FUCK was put in the medical documents of the British Imperial Army soldiers in detecting sexually transmitted diseases. According to another version, FUCK is an acronym for Fornication Under Consent of the King - «fornication with the consent of the King. This poster allegedly posted in ancient Britain at the doors of houses where people were having sex - the sex of people not belonging to the royal family was allowed only with the consent of the king. A third version, FUCK interpreted as Forced Unnatural Carnal Knowledge - «forced unnatural carnal knowledge", is a legal term for rape in the XVI century. Finally, the most popular is the version according to which the word comes from For Unlawful Carnal Knowledge - «for the unlawful carnal knowledge". The verdict, according to the version that first appeared in Playboy in 1970, wrote that in the documents with accusations of prostitutes in the XIX century, or on the gallows, where they hung whores and men who use their services, in earlier centuries. Of particular popularity of this explanation of origin of the word FUCK gave, in addition to articles in the magazine Playboy, self-titled album Van Halen.