September 14

Domitian becomes Roman emperor following the death of his brother Titus.

Following the sudden death of his elder brother Titus, Domitian assumed the imperial throne, going on to rule Rome for fifteen years with an increasingly autocratic and, according to many ancient sources, tyrannical style of governance that ultimately led to his assassination.

Harun al-Rashid becomes Abbasid caliph upon his brother's death, in an episode known as the Night of the Three Caliphs.

In a rapid and unusual succession, the Abbasid caliphate saw its throne pass through three different claimants within a single day following the death of Caliph al-Hadi, before Harun al-Rashid emerged as the recognized ruler, beginning a reign later celebrated as a golden age of Islamic civilization.

Irish High King Niall Glundub is killed fighting Viking forces at the Battle of Islandbridge.

Niall Glundub, High King of Ireland, was killed leading Irish forces against a Viking army near Dublin, a defeat that nonetheless became memorialized in Irish poetry and legend, with Niall's descendants later founding one of medieval Ireland's most prominent royal dynasties.

Crusader forces under Roger of Salerno defeat a larger Seljuk army at the Battle of Sarmin.

Crusader forces led by Roger of Salerno, prince of Antioch, achieved an unexpected victory over a numerically superior Seljuk Turkish army near Sarmin in northern Syria, temporarily securing the Principality of Antioch's borders during the ongoing Crusader presence in the Levant.

Minamoto no Yoritomo suffers defeat at the Battle of Ishibashiyama during Japan's Genpei War.

During Japan's chaotic Genpei War between rival samurai clans, Minamoto no Yoritomo suffered an early defeat at Ishibashiyama, forcing him to flee, though he later regrouped and ultimately triumphed, establishing the Kamakura shogunate that governed Japan for over a century.

The Catholic practice of perpetual Eucharistic adoration formally begins in Avignon, France.

In Avignon, France, a continuous, unbroken tradition of Eucharistic adoration, the Catholic practice of venerating consecrated bread believed to be the body of Christ, formally began, a devotional practice that has continued in various forms and locations within the Church for centuries since.

President William McKinley dies from gunshot wounds inflicted eight days earlier, and Theodore Roosevelt succeeds him.

President McKinley succumbed to gangrene from gunshot wounds suffered over a week earlier, and Vice President Theodore Roosevelt was sworn in as his successor at just 42 years old, becoming the youngest president in American history and ushering in an era of progressive reform.

The Organization of Petroleum Exporting Countries is established as an international coalition of oil-producing nations.

Representatives from Iran, Iraq, Kuwait, Saudi Arabia, and Venezuela met in Baghdad to establish an organization aimed at coordinating petroleum production policy and prices among major oil-exporting nations, a coalition that grew to wield enormous influence over global energy markets in subsequent decades.

Lebanese president-elect Bachir Gemayel is assassinated before taking office.

Lebanon's Christian president-elect was killed when a bomb destroyed his political party's headquarters just weeks before he was due to take office, a killing that triggered a notorious massacre of Palestinian refugees by allied militias in the following days amid Lebanon's ongoing civil war.

Queen Elizabeth II's coffin is ceremonially processed to Westminster Hall to begin her four-day lying in state.

Following her death at Balmoral Castle, Queen Elizabeth II's coffin was transported to London and processed through the streets to Westminster Hall, where it lay in state for four days, drawing enormous crowds of mourners who queued for many hours to pay their respects.