*A lot of english or american names for girls are given to boys in France, the contrary too :)
*Tristan is traditionally Cornish, with domains in Brittany (Bretagne), which derives its name, apparently, from all the British who piled in there at the collapse of the Western Roman Empire, at about the same time as the Angles were arriving on the east coast of Britain and rather high-handedly re-naming the place "Angle-land", by which they meant the whole island.   Mediaeval French poems about Tristan, therefore, distinguish between "Bretagne", south of the Channel, and "Engleterre", north of it, a distinction which which would probably have annoyed the socks off a manly British hero like Tristan.   The English, as far as I know, only started to refer to the island as "Britain"  when James VI of Scotland became James I of England and Wales in 1603.  In the meantime, the Celtic-language inhabitants of Cornwall had long ago been conquered by the Saxons of southern England and the English had frequently made common cause with the Bretons, the cousins of the Cornish,  against their common enemy, the French.   On the other hand, in 1066, William the Bastard , Duke of Normandy, had been able to deploy a fair number of Breton troops at Hastings, where the Saxon rule of England, established by Alfred and his successors, was extinguished.   Recent research, certainly pretty controversial, speculates that the Saxons did not arrive along with the Angles and after the departure of the Romans (the traditional assumption), but had been in Britain from before the Roman conquest.   That could explain why the Scots Gaelic ("Sasunnach") and Welsh ("Saesneg") words for "English" both refer to the Saxons, rather than to the Angles who were geographically closer to Scotland and Wales, but may have arrived many centuries later.

Still, Tristan's a bloke, however you look at it..