Births on January 9

Luísa Todi, Portuguese soprano and actress (d. 1833)

Luísa Rosa de Aguiar Todi (1753–1833) was a popular and successful Portuguese mezzo-soprano opera singer.

17 Feb

Gregorian calendar
In Sweden February 17 is followed by March 1 as the country moves from the Julian calendar to the Gregorian calendar.
1 May

International Code of Botanical Nomenclature
Publication of Species Plantarum by Linnaeus, and the formal start date of plant taxonomy adopted by the International Code of Botanical Nomenclature.