Editing 1802 (section)

=== April–June ===
* April 10 – The [[Great Trigonometrical Survey]] of India begins with the measurement of a baseline near [[Chennai|Madras]].
* April 12 — Beethoven leaves [[Vienna]] for a small nearby Austrian village named [[Heiligenstadt, Vienna |Heiligenstadt]] where he would cope with his declining mental and physical health including his growing deafness. He would stay until October and there he would write an unsent letter to his brothers called the [[Heiligenstadt Testament]]. In the letter, Beethoven contemplates suicide but it was his passion for the art of music that prevented him so.
* April 21 – About 12,000 Wahhabi Sunnis under the command of [[Abdul-Aziz bin Muhammad]], the second ruler of the First Saudi State attack and [[Wahhabi sack of Karbala|sack Karbala]], kill between 2,000 and 5,000 inhabitants and plunder the tomb of [[Husayn ibn Ali]], grandson of [[Muhammad]] and son of [[Ali ibn Abi Talib]].
* April 26 – A general amnesty signed by [[Napoleon]] allows all but about 1,000 of the most notorious [[émigré]]s of the [[French Revolution]] to return to France as part of a conciliatory gesture to make peace with the various factions of the ''[[Ancien Régime]]'' that ultimately consolidates his own rule.
* May 19 – Napoleon establishes the French [[Legion of Honour]] (''Légion d'honneur'').
* May 20 – By the [[Law of 20 May 1802]], [[Napoleon]] reinstates slavery in the [[French colonies]], revoking its abolition in the [[French Revolution]].
* May – Madame [[Marie Tussaud]] first exhibits her [[wax sculpture]]s in London, having been commissioned, during the [[Reign of Terror]] in France, to make death masks of the victims.<ref>Pamela Pilbeam, ''Madame Tussaud: And the History of Waxworks'' (A&C Black, 2006) p65</ref>
* June – The first account of [[Thomas Wedgwood (photographer)|Thomas Wedgwood]]'s experiments in photography is published by [[Humphry Davy]] in the ''Journal of the Royal Institution'' in London.<ref>"An Account of a method of copying Painting upon Glass and making profiles, by the agency of Light upon Nitrate of Silver." Invented by T. Wedgwood, Esq. with Observations by H. Davy.</ref><ref>Robert Hirsch, ''Seizing the Light: A Social & Aesthetic History of Photography'' (Taylor & Francis, 2017)</ref> Since a fixative for the image has not yet been developed, the early photographs quickly fade.
* June 1
** The [[United States Patent and Trademark Office]] is established within the [[Department of State]].
** At [[Huế]], shortly before his conquest of Tonkin, Nguyen Anh is crowned as the Emperor [[Gia Long]], the first ruler of the [[Nguyễn dynasty]] in Vietnam.<ref>"Nguyen Anh (Emperor Gia Long)", by Nguyen The Anh, in ''Southeast Asia: A Historical Encyclopedia, from Angkor Wat to East Timor'', ed. by [[Keat Gin Ooi]] (ABC-CLIO, 2004) p870</ref>
* June 2 – [[Indigenous Australian]] [[Pemulwuy]], a leader of the resistance to European settlement of Australia, is shot dead by [[Henry Hacking]].
* June 8 – Haitian revolutionary [[Toussaint Louverture]] is seized by French troops and imprisoned at the [[Fort de Joux]].