Skip to content
Almanaccolo

Holidays and observances

September

Holidays and observances on September 23

17 holidays and special days are celebrated on September 23 around the world.

Holidays and observances

Frequently asked questions

What is celebrated on September 23?

17 observances are celebrated on September 23 around the world: Christian feast day: Adomnán, Christian feast day: Cissa of Crowland (or of Northumbria), Christian feast day: Blessed Francisco de Paula Victor, Christian feast day: Padre Pio, Christian feast day: Pope Linus, Christian feast day: Sossius. The list gathers national holidays, international days and religious or civil observances falling on this date in different countries, as recorded on Wikipedia. Some are fixed and recur on the same day every year; others depend on the local calendar. Each links to the article explaining its origin and meaning.

What happened on September 23?

43 documented historical events happened on September 23, from antiquity to the present day. The best known is this: Pope Callixtus II and Holy Roman emperor Henry V agreed the Concordat of Worms (pictured), ending the Investiture Controversy. On the same day, in another year: The Battle of Arnemuiden, in which a French force defeats the English, is the first naval battle of the Hundred Years' War. On Almanaccolo every event is listed in chronological order, grouped by century, and links to the Wikipedia article it comes from, so you can always read further or check the source. Alongside the events you find who was born and who died on this date, and which observances are celebrated around the world.

Keep exploring

Free app

Every day’s history, in your pocket

Almanaccolo greets you each morning with the almanac of the day, sunrise and sunset times and your saved events.

  • Today’s almanac, every morning
  • Save the events that strike you
  • Sunrise, sunset and weather for your city
  • Free, no account required
History in your pocket