July 2437 – Emperor Valentinian III begins his reign over the Western Roman Empire. His mother Galla Placidia ends her regency, but continues to exercise political influence at the court in Rome. 626 – Li Shimin, the future Emperor Taizong of Tang, ambushes and kills his rival brothers Li Yuanji and Li Jiancheng in the Xuanwu Gate Incident. 706 – In China, Emperor Zhongzong of Tang inters the bodies of relatives in the Qianling Mausoleum, located on Mount Liang outside Chang'an.
July 4362 BC – Battle of Mantinea: The Thebans, led by Epaminondas, defeated the Spartans. 414 – Emperor Theodosius II, age 13, yields power to his older sister Aelia Pulcheria, who reigned as regent and proclaimed herself empress (Augusta) of the Eastern Roman Empire. 836 – Pactum Sicardi, a peace treaty between the Principality of Benevento and the Duchy of Naples, is signed. 993 – Ulrich of Augsburg is canonized as a saint. 1054 – A supernova, called SN 1054, is seen by Chinese Song dynasty, Arab, and possibly Amerindian observers near the star Zeta Tauri.
1888In Germany, 1888 is known as the Year of the Three Emperors. Currently, it is the year that, when written in Roman numerals, has the most digits (13). The next year that also has 13 digits is the year 2388. The record will be surpassed as late as 2888, which has 14 digits. January 3 – The 91-centimeter telescope at Lick Observatory in California is first used. January 12 – The Schoolhouse Blizzard hits Dakota Territory, the states of Montana, Minnesota, Nebraska, Kansas, and Texas, leaving 235 dead, many of them children on their way home from school.