March 30

598 – Balkan Campaign: 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 hordes are decimated by the plague. 1282 – The people of Sicily rebel against the Angevin king Charles I, in what becomes known as the Sicilian Vespers. 1296 – Edward I sacks Berwick-upon-Tweed, during armed conflict between Scotland and England. 1699 – Guru Gobind Singh establishes the Khalsa in Anandpur Sahib, Punjab. 1815 – Joachim Murat issues the Rimini Proclamation which would later inspire Italian unification. 1818 – 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. 1822 – The Florida Territory is created in the United States. 1841 – The National Bank of Greece is founded in Athens. 1842 – Ether anesthesia is used for the first time, in an operation by the American surgeon Dr. Crawford Long. 1844 – One of the most important battles of the Dominican War of Independence from Haiti takes place near the city of Santiago de los Caballeros. 1855 – Origins of the American Civil War: "Border Ruffians" from Missouri invade Kansas and force election of a pro-slavery legislature. 1856 – The Treaty of Paris is signed, ending the Crimean War. 1861 – Discovery of the chemical elements: Sir William Crookes announces his discovery of thallium. 1863 – Danish prince Wilhelm Georg is chosen as King George of Greece. 1867 – Alaska is purchased from Russia for $7.2 million, about two cents/acre ($4.19/km2), by United States Secretary of State William H. Seward. 1870 – Texas is readmitted to the United States Congress following Reconstruction. 1885 – The Battle for Kushka triggers the Panjdeh Incident which nearly gives rise to war between the Russian and British Empires.