Wikipedia:Selected anniversaries/September 18
This is a list of selected September 18 anniversaries that appear in the "On this day" section of the Main Page. To suggest a new item, in most cases, you can be bold and edit this page. Please read the selected anniversaries guidelines before making your edit. However, if your addition might be controversial or on a day that is or will soon be on the Main Page, please post your suggestion on the talk page instead.
Please note that the events listed on the Main Page are chosen based more on relative article quality and to maintain a mix of topics, not based solely on how important or significant their subjects are. Only four to five events are posted at a time and thus not everything that is "most important and significant" can be listed. In addition, an event is generally not posted this year if it is also the subject of the scheduled featured article or picture of the day.
To report an error when this appears on the Main Page, see Main Page errors. Please remember that this list defers to the supporting articles, so it is best to achieve consensus and make any necessary changes there first.
September 18: National Day in Chile
- 96 – Following the assassination of Roman Emperor Domitian, the Roman Senate appointed Nerva (bust pictured), the first of the Five Good Emperors, to succeed him.
- 324 – 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.
- 1809 – The second theatre of the Royal Opera House in London opened after a fire destroyed the original theatre one year earlier.
- 1810 – Patria Vieja, the first stage of the Chilean War of Independence, began.
- 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.