Wikipedia:Selected anniversaries/September 27
- 1540 - Pope Paul III gave the final approval to the formation of the Society of Jesus by St. Ignatius of Loyola.
- 1940 - The Tripartite Pact was signed in Berlin by the major Axis Powers — Nazi Germany, Fascist Italy and the Empire of Japan.
- 1983 - Richard Stallman announced the GNU project to develop a free Unix-like operating system.
- 1996 - The Taliban drove President Burhanuddin Rabbani out of the Afghan capital of Kabul, executed former President Mohammad Najibullah, and established the Islamic Emirate of Afghanistan.
Recent days: September 26 – September 25 – September 24