Today's selected anniversaries: 31st May 2024 1223: Mongol invasion of Kievan Rus': Mongol forces defeated a Kievan Rus' army at the Kalka River in present-day Ukraine. https://en.wikipedia.org/wiki/Battle_of_the_Kalka_River 1468: Cardinal Bessarion announced his donation of 746 Greek and Latin codices to the Republic of Venice, forming the Biblioteca Marciana. https://en.wikipedia.org/wiki/Biblioteca_Marciana 1935: An earthquake registering 7.7 Mw struck Balochistan in British India, now part of Pakistan, killing between 30,000 and 60,000 people. https://en.wikipedia.org/wiki/1935_Quetta_earthquake 2013: A tornado struck Central Oklahoma, killing 8 people and injuring more than 150. https://en.wikipedia.org/wiki/2013_El_Reno_tornado