What day of the week was May 13, 1861?

The day of the week May 13th, 1861 fell on was a Monday.

American Civil War: Queen Victoria of the United Kingdom issues a "proclamation of neutrality" which recognizes the breakaway states as having belligerent rights. The Great Comet of 1861 is discovered by John Tebbutt of Windsor the New South Wales, Australia. Pakistan's (then a part of British India) first railway line opens the from Karachi to Kotri.