Switzerland has four official languages: German, French, Italian and Romansch. What historical event or events prompted this. As far as I am aware this is the only country in Europe with three or more official languages

by thomastittley
Bayoris

This does not answer your question, but Luxembourg also has three official languages: Luxembourgish, French, and German. Belguim has three: Dutch, French and German. Several countries also have three or more "official minority languages": Russia, for example, has 25 languages that are official in one part or another, though only Russian is official throughout the whole territory.