Deaths on April 4

Jérôme Lalande, French astronomer and academic (b. 1732)

Joseph Jérôme Lefrançois de Lalande (French: [lalɑ̃d]; 11 July 1732 – 4 April 1807) was a French astronomer, freemason and writer.

7 Feb

Battle of Eylau
Napoleonic Wars: Napoleon finds Bennigsen's Russian forces taking a stand at Eylau. After bitter fighting, the French take the town, but the Russians resume the battle the next day.
19 Feb

Aaron Burr
Former Vice President of the United States Aaron Burr is arrested for treason in Wakefield, Alabama and confined to Fort Stoddert.
12 Apr

Fort Ricasoli
The Froberg mutiny ends when the remaining mutineers blow up the magazine of Fort Ricasoli.
22 May

Aaron Burr
A grand jury indicts former Vice President of the United States Aaron Burr on a charge of treason.
20 Jul

Internal combustion engine
Nicéphore Niépce is awarded a patent by Napoleon for the Pyréolophore, the world's first internal combustion engine, after it successfully powered a boat upstream on the river Saône in France.