# Letter to André Weil

(written in 1967, appeared 2015 in Emil Artin and beyond---class field theory and L-functions)

Editorial comments: In January of 1967, while he was at Princeton University, Langlands wrote a letter of 17 hand-written pages to Andre Weil outlining what quickly became known as the Langlands conjectures'. This letter even today is worth reading carefully, although its notation is by present standards somewhat clumsy. It was in this letter that what later became known as the $L$-group' first made its appearance, like Gargantua, surprisingly mature. Because of its historic importance, we give here two versions of this letter, as well as a pair of supplementary notes accompanying it. A typed copy of this letter, made at Weil's request for easier reading, circulated widely among specialists in the late sixties and seventies. The covering note from Harish-Chandra has been helpful in establishing a date for the letter, which is itself undated.