September 18

Roman Emperor Domitian is assassinated in a palace conspiracy involving his wife and Praetorian officials.

Roman Emperor Domitian was stabbed to death in a palace conspiracy involving his own wife, Domitia Longina, and several Praetorian Guard officers who feared for their lives under his increasingly paranoid and repressive rule, ending the Flavian dynasty's direct line of succession.

Constantine the Great defeats rival emperor Licinius at the Battle of Chrysopolis, consolidating sole control of the Roman Empire.

Constantine the Great decisively defeated his co-emperor and rival Licinius at Chrysopolis near Byzantium, eliminating the last significant challenger to his authority and reunifying the Roman Empire under a single ruler for the first time in decades. Constantine's subsequent decision to relocate the empire's capital eastward to the renamed city of Constantinople reshaped the empire's political and cultural center of gravity for centuries.

Norwegian King Harald Hardrada lands forces at the mouth of the Humber River, beginning his invasion of England.

Norwegian King Harald Hardrada landed a substantial invasion force in northern England, beginning a campaign in alliance with the rebellious English earl Tostig that would culminate in Harald's defeat and death at the Battle of Stamford Bridge just days before William the Conqueror's own separate invasion at Hastings, together forming one of the most eventful years in medieval English history.

George Washington lays the cornerstone of the United States Capitol building.

President Washington personally participated in the Masonic ceremony laying the cornerstone of the United States Capitol building, using a silver trowel and ceremonial apron as part of the ritual. The structure would grow considerably over subsequent decades, including a major expansion and the addition of its iconic cast-iron dome, to become the enduring symbolic seat of the American legislative branch.

The Royal Opera House opens in London.

London's Royal Opera House opened its doors in Covent Garden, becoming one of the world's preeminent venues for opera and ballet performance, though the current building represents a later Victorian-era reconstruction following fires that destroyed two earlier versions of the theater. The venue remains home to both the Royal Opera and the Royal Ballet companies today.

The New-York Daily Times, later renamed The New York Times, publishes its first edition.

Henry Jarvis Raymond and George Jones published the inaugural edition of what was then called The New-York Daily Times, a newspaper that would evolve into The New York Times, eventually becoming one of the most influential and widely respected news organizations in the world.

The Columbia Broadcasting System, later known as CBS, goes on the air.

The Columbia Broadcasting System began radio operations under the leadership of a small group of investors, eventually expanding into television under the guidance of executive William S. Paley and growing into one of the major American broadcast networks. CBS played a significant role in shaping broadcast news standards and popular entertainment programming throughout much of the twentieth century.

Japan stages the Mukden Incident as a pretext for occupying Manchuria.

Japanese military officers staged a bombing of a South Manchurian Railway line and falsely blamed Chinese dissidents, using the fabricated incident as justification to launch a full military occupation of Manchuria, a significant early step toward Japan's broader imperial expansion in Asia.

Voyager 1 captures the first photograph showing both Earth and the Moon together in a single frame.

As NASA's Voyager 1 spacecraft looked back toward its home solar system from a distance of about 4 billion miles, its cameras captured a striking image showing both Earth and the Moon together, one of the earliest photographs to depict the two celestial bodies in a single frame from deep space.

Scotland votes against independence from the United Kingdom in a referendum, by a margin of 55 to 45 percent.

Scottish voters rejected a proposal for full independence from the United Kingdom in a closely watched referendum, with 55 percent voting to remain part of the UK, though the debate over Scottish independence has continued to resurface in British politics in the years since.