\ was invented so that ∧ and ∨ could be written /\ and \/. In retrospect, a mistake. Original ASCII (1963) had ↑, but it was converted to ^ in 1967 so that it

\ was invented so that ∧ and ∨ could be written /\ and \/. In retrospect, a mistake. Original ASCII (1963) had ↑, but it was converted to ^ in 1967 so that it could double as a circumflex. (Also ←, which was a good assignment operator; it's too bad _ didn't replace \ instead.)