A Commit in 1970?

Yes, you can! Git lets you backdate commits by setting GIT_COMMITTER_DATE.

GIT_COMMITTER_DATE="1970-01-01T00:00:00Z" git commit --date="1970-01-01T00:00:00Z" -m "hello, world!"

Fun fact: 1970 is the "year zero" for computers, because Unix time (the number of seconds since the epoch) starts at 0 on January 1, 1970.