Misc: What was the predecessor of the United Nations?

Questions

christmas became a national holiday in the u.s in 1879, 1890 or 1895?

during the u.s civil war, what did 22 union army blacks win?

during the u.s civil war, how many blacks served in the union army?

during the u.s civil war, how many union army blacks gave their lives?

in the middle ages, where did people believe the seat of intelligence was?