📅 Today in HistoryMarch 30

Avar-Byzantine wars: The Avars lift the siege at the Byzantine stronghold of Tomis. Their leader Bayan I retreats north of the Danube River after the Avaro-Slavic army is decimated by the plague.

The people of Sicily rebel against the Angevin king Charles I, in what becomes known as the Sicilian Vespers.

Edward I sacks Berwick-upon-Tweed, during armed conflict between Scotland and England.

Guru Gobind Singh establishes the Khalsa in Anandpur Sahib, Punjab.

Joachim Murat issues the Rimini Proclamation, among the earliest calls for Italian unification.

Physicist Augustin Fresnel reads a memoir on optical rotation to the French Academy of Sciences, reporting that when polarized light is "depolarized" by a Fresnel rhomb, its properties are preserved in any subsequent passage through an optically-rotating crystal or liquid.

The Florida Territory is created in the United States.

The National Bank of Greece is founded in Athens.

Ether anesthesia is used for the first time, in an operation by the American surgeon Dr. Crawford Long.

One of the most important battles of the Dominican War of Independence from Haiti takes place near the city of Santiago de los Caballeros.