Something about unix time? Isn't the earliest moment in unix time around December 1900? Epoch - 2^31 seconds? I'm betting it's something about that plus some tricky nonsense I don't have the energy figuring out (assuming that I could). I guess spoiler alert...

I used to love puzzles like this when I was younger, but I think I've lost the patience for them now.

EDIT: ah, no, it's December 13, 1901. Never mind!