April 12240 – Shapur I becomes co-emperor of the Sasanian Empire with his father Ardashir I. 467 – Anthemius is elevated to Emperor of the Western Roman Empire. 627 – King Edwin of Northumbria is converted to Christianity by Paulinus, bishop of York. 1012 – Duke Oldřich of Bohemia deposes and blinds his brother Jaromír, who flees to Poland. 1204 – The Crusaders of the Fourth Crusade breach the walls of Constantinople and enter the city, which they completely occupy the following day.
April 15769 – The Lateran Council ends by condemning the Council of Hieria and anathematizing its iconoclastic rulings. 1071 – Bari, the last Byzantine possession in southern Italy, is surrendered to Robert Guiscard. 1450 – Battle of Formigny: Toward the end of the Hundred Years' War, the French attack and nearly annihilate English forces, ending English domination in Northern France. 1632 – Battle of Rain: Swedes under Gustavus Adolphus defeat the Holy Roman Empire during the Thirty Years' War.
August 948 BC – Caesar's Civil War: Battle of Pharsalus: Julius Caesar decisively defeats Pompey at Pharsalus and Pompey flees to Egypt. 378 – Gothic War: Battle of Adrianople: A large Roman army led by Emperor Valens is defeated by the Visigoths. Valens is killed along with over half of his army. 1173 – Construction of the campanile of the Cathedral of Pisa (now known as the Leaning Tower of Pisa) begins; it will take two centuries to complete. 1329 – Quilon, the first Indian Christian Diocese, is erected by Pope John XXII; the French-born Jordanus is appointed the first Bishop.
February 29February 29 is a leap day or "leap year day", an intercalary date added periodically to leap years in the Julian and Gregorian calendars. It is the 60th day of a leap year in both calendars, and 306 days remain until the end of the leap year. It is also the last day of February on leap years with the exception of 1712 in Sweden. It is also the last day of meteorological winter in Northern Hemisphere and the last day of meteorological summer in the Southern Hemisphere on leap years.
February 101258 – Mongol invasions: Baghdad falls to the Mongols, bringing the Islamic Golden Age to an end. 1306 – In front of the high altar of Greyfriars Church in Dumfries, Robert the Bruce murders John Comyn, sparking the revolution in the Wars of Scottish Independence. 1355 – The St Scholastica Day riot breaks out in Oxford, England, leaving 63 scholars and perhaps 30 locals dead in two days. 1502 – Vasco da Gama sets sail from Lisbon, Portugal, on his second voyage to India.
February 24484 – King Huneric of the Vandals replaces Nicene bishops with Arian ones, and banishes some to Corsica. 1303 – The English are defeated at the Battle of Roslin, in the First War of Scottish Independence. 1386 – King Charles III of Naples and Hungary is assassinated at Buda. 1525 – A Spanish-Austrian army defeats a French army at the Battle of Pavia. 1527 – Coronation of Ferdinand I as the king of Bohemia in Prague. 1538 – Treaty of Nagyvárad between Holy Roman Emperor Ferdinand I and King John Zápolya of Hungary and Croatia.
February 23303 – Roman emperor Diocletian orders the destruction of the Christian church in Nicomedia, beginning eight years of Diocletianic Persecution. 532 – Byzantine emperor Justinian I lays the foundation stone of a new Orthodox Christian basilica in Constantinople – the Hagia Sophia. 628 – Khosrow II, last Sasanian shah of Iran, is overthrown. 705 – Empress Wu Zetian abdicates the throne, restoring the Tang dynasty. 1455 – Traditionally the date of publication of the Gutenberg Bible, the first Western book printed with movable type.
February 21452 or 453 – Severianus, Bishop of Scythopolis, is martyred in Palestine. 1245 – Thomas, the first known Bishop of Finland, is granted resignation after confessing to torture and forgery. 1440 – The Prussian Confederation is formed. 1613 – Mikhail I is unanimously elected Tsar by a national assembly, beginning the Romanov dynasty of Imperial Russia. 1797 – A force of 1,400 French soldiers invaded Britain at Fishguard in support of the Society of United Irishmen. They were defeated by 500 British reservists.
February 61579 – The Archdiocese of Manila is made a diocese by a papal bull with Domingo de Salazar being its first bishop. 1685 – James II of England and VII of Scotland is proclaimed King upon the death of his brother Charles II. 1694 – The warrior queen Dandara, leader of the runaway slaves in Quilombo dos Palmares, Brazil, is captured and commits suicide rather than be returned to a life of slavery. 1778 – American Revolutionary War: In Paris the Treaty of Alliance and the Treaty of Amity and Commerce are signed by the United States and France signaling official recognition of the new republic.
February 562 – Earthquake in Pompeii, Italy. 1576 – Henry of Navarre abjures Catholicism at Tours and rejoins the Protestant forces in the French Wars of Religion. 1597 – A group of early Japanese Christians are killed by the new government of Japan for being seen as a threat to Japanese society. 1783 – In Calabria, a sequence of strong earthquakes begins. 1810 – Peninsular War: Siege of Cádiz begins. 1818 – Jean-Baptiste Bernadotte ascends to the thrones of Sweden and Norway.
