> LISP was the first reasonably popular functional language (maybe the first functional language, period), long predating most of the rest.

Hell, it was the second high-level language, period, after Fortran but before COBOL.

Depends on how you define functional language, but I think from the beginning it let you pass around and manipulate functions -- "first class data type" -- which is pretty core. And had recursion and recursive data types, though it wasn't until the Scheme dialect that someone insisted tail calls be efficient.