Births on May 31

Johann Georg Baiter, Swiss philologist and scholar (d. 1887)

Johann Georg Baiter (May 31, 1801 – October 10, 1877) was a Swiss philologist and textual critic.

1 Jan

United Kingdom of Great Britain and Ireland
The legislative union of Kingdom of Great Britain and Kingdom of Ireland is completed to form the United Kingdom of Great Britain and Ireland.
23 Mar

Paul I of Russia
Tsar Paul I of Russia is struck with a sword, then strangled, and finally trampled to death inside his bedroom at St. Michael's Castle.
2 Apr

Battle of Copenhagen (1801)
French Revolutionary Wars: The British capture the Danish fleet.
10 May

Barbary pirates
First Barbary War: The Barbary pirates of Tripoli declare war on the United States of America.
1 Aug

Action of 1 August 1801
First Barbary War: The American schooner USS Enterprise captures the Tripolitan polacca Tripoli in a single-ship action off the coast of modern-day Libya.