Medallion

September 18: National Day in Chile.

96 – Following the assassination of Roman Emperor Domitian, the Roman Senate appointed Nerva, the first of the Five Good Emperors, to succeed him.
323 – Constantine the Great decisively defeated Licinius in the Battle of Chrysopolis, establishing Constantine's sole control over the Roman Empire, and ultimately leading to the conversion of the whole empire to Christianity.
1895 – Daniel David Palmer (pictured) gave the first chiropractic adjustment to deaf janitor Harvey Lillard, reportedly resulting in a restoration of the man's hearing.
1931 – The Mukden Incident: A section of the Japanese-built South Manchuria Railway was destroyed, providing an excuse for the Japanese to blame the act on Chinese dissidents, and thus giving a pretext for the Japanese occupation of Manchuria.
1961 – En route to negotiate a ceasefire between Katanga troops and United Nations forces, the plane carrying UN Secretary-General Dag Hammarskjöld crashed under mysterious circumstances near Ndola in Northern Rhodesia, killing him and 15 others on board.