Copied and pasted from user Leelogs at Yahoo Answers:
The condom in fact derives from the Roman Empire and was indeed made
of sheep gut, but it was not much used (the legion was laid low with
herpes when the Goths invaded).
The French aristocracy used them widely, however, as early as the 17th
century. Madame de Sevigne, writing in 1671, dismissed the use of
condoms as "armour against enjoyment and a spider's web against
danger". Seventy years later, the Venetian adventurer Casanova became
its most ardent supporter.
In Britain the condom was viewed as a dirty Continental fetish,
something for harlots or sailors. They remained curious about them,
however, and young men taking the Grand Tour (through Europe via
France, Italy and Greece to Constantinople and beyond) would, if
sending a message home with a returning tourist, enclose a condom...
thus a French letter. The culture and culinary clash of the English /
French on the Grand Tour also gave rise to the terms "Rostbifs"
(English) and "Frogs" (French).
The French practice of calling them English Coats derives simply from
the eternal enmity of these two countries; ever keen to credit each
other with things regarded as unpleasant. Ascribing "bad" habits and
plagues to your nearest neighbours has always been common in Europe;
during the 1917-1920 influenza pandemic the disease was called Spanish
Flu in southern France, German Fever in Belgium, Greek Flu in Turkey
and Arabian Flu in Greece.
On the subject of sex consider "buggery" from "bulgary" - what the
English considered to be the practice of Bulgars - something the
Italians (and today Americans) have long refered to as "Greek". There
are also references to "Tartary" - nasty stuff the Tartars (Turks)
were thought to get up to. Nothing brings out racial suspicion like
sex!