English form of name translated into French

Okay, I know that James is Jacques, John is Jean, Henry is Henri, and so on.

What would be the French form of the name William?

Williem?

Guillaume.

This link has a blank for the french version of william.

commasense is correct, it’s Guillaume, as in Guillaume Tell.

Which is far more reasonable than the Italian version, Guiglielmo.

Thanks everyone! I should have guessed. The Spanish form is Guillermo.

I’ll note that William, as is, is gaining popularity in the French-speaking world. This was my impression and this site seems to support it. William was the 77th most popular name in France in 2002. In the Lauzère department, it was in 10th place. By comparison, Guillaume seems to be loosing popularity, dropping to 38th rank, down from 4th in 1984. Here’s the list of the most popular names in France in 2002.