Births on June 21

Arthur Cowper Ranyard, English astrophysicist and astronomer (d. 1894)

Arthur Cowper Ranyard (21 June 1845 – 14 December 1894) was an English astrophysicist.

11 Mar

Treaty of Waitangi
Flagstaff War: Unhappy with translational differences regarding the Treaty of Waitangi, chiefs Hone Heke, Kawiti and Māori tribe members chop down the British flagpole for a fourth time and drive settlers out of Kororareka, New Zealand.
13 Mar

Violin Concerto (Mendelssohn)
Felix Mendelssohn's Violin Concerto receives its première performance in Leipzig with Ferdinand David as soloist.
19 May

Franklin's lost expedition
Captain Sir John Franklin and his ill-fated Arctic expedition depart from Greenhithe, England.
13 Oct

United States Congress
A majority of voters in the Republic of Texas approve a proposed constitution that, if accepted by the U.S. Congress, will make Texas a U.S. state.
20 Nov

Battle of Vuelta de Obligado
Anglo-French blockade of the Río de la Plata: Battle of Vuelta de Obligado.