Wikipedia:Selected anniversaries/April 13
April 13: Thai New Year's Day, Vaisakhi in India.
- 1598 - King Henry IV of France (pictured) issued the Edict of Nantes, allowing freedom of religion to the Huguenots.
- 1742 - Messiah, an oratorio by George Frideric Handel, premiered in Dublin.
- 1860 - The Pony Express, the first mail service across the North American continent from the Missouri River to the Pacific coast, was successfully completed for the first time.
- 1943 - World War II: Germany announced the discovery of a mass grave of Polish prisoners-of-war executed by Soviet forces in the Katyn Forest Massacre.
- 1984 - Indian forces launched a preemptive attack on the disputed Siachen Glacier region of Kashmir, triggering a military conflict with Pakistan.