March 31 in History

Minervina was either the first wife or concubine of Constantine I, and the mother of his eldest son and future caesar Crispus. Little is known of her life. Her birth and death dates are unknown.

In 1173–1174, a conspiracy took place in Cairo in favour of restoring the Isma'ili Shi'a Fatimid Caliphate, which had been abolished in 1171 by Saladin, the first Ayyubid ruler of Egypt. The conspiracy, which is known only from sources favourable to Saladin, was led by elites of the fallen Fatimid regime, and aimed to seize control over Cairo by taking advantage of Saladin's absence from the city on campaign. To this end, they are alleged to have contacted the Crusaders of the Kingdom of Jerusalem, inviting them to invade Egypt in order to lure Saladin away. The conspirators are also said to have contacted the Nizari Isma'ili Order of Assassins to assassinate Saladin. The veracity of these claims is disputed by modern historians, who consider them inventions aimed to discredit the conspirators. In the event, the conspiracy was betrayed to Saladin, although the sources differ on how exactly. Some even hold that the conspiracy was precipitated by Saladin as a political purge, or as a means of demonstrating to his increasingly hostile nominal master, the emir of Aleppo and Damascus, Nur al-Din Zengi, that Egypt was still unruly and that Saladin was indispensable to keep the opposition in check. The Ayyubid ruler struck on 31 March 1174 and arrested the ringleaders, among them the celebrated poet Umara al-Yamani. The chief conspirators were executed at the Bayn al-Qasrayn square from 6 April until 23 May, while others were exiled. A pro-Fatimid revolt in Upper Egypt followed, but was suppressed in September by Saladin's brother, al-Adil.

Ferdinand II was King of Aragon from 1479 until his death in 1516. As the husband and co-ruler of Queen Isabella I of Castile, he was also King of Castile from 1475 to 1504. He reigned jointly with Isabella over a dynastically unified Spain; together, they are known as the Catholic Monarchs. Ferdinand is considered the de facto first king of Spain, and was described as such during his reign, even though, legally, Castile and Aragon remained two separate kingdoms until they were formally united by the Nueva Planta decrees issued between 1707 and 1716.

The Long Parliament was an English Parliament which nominally lasted from 1640 until 1660, making it the longest-lasting Parliament in English and British history. It followed the fiasco of the Short Parliament, which had convened for only three weeks during the spring of 1640 after an 11-year parliamentary absence. In September 1640, King Charles I issued writs summoning a parliament to convene on 3 November 1640. He intended it to pass financial bills, a step made necessary by the costs of the Bishops' Wars against Scotland. The Long Parliament received its name from the fact that, by an act of Parliament, the Parliament Act 1640, it stipulated it could be dissolved only with agreement of the members; and those members did not agree to its dissolution until 16 March 1660, after the English Civil War and near the close of the Interregnum.

Benjamin Hoadly was an English clergyman, who was successively Bishop of Bangor, of Hereford, of Salisbury, and finally of Winchester. He is best known as the initiator of the Bangorian Controversy.