Based on the search results, September 23, 2023, is a Saturday and the 266th day of the year, with 99 days left in 2023. It is also a day with several observances and holidays, including:

• National Singles Day
• International Day of Sign Languages
• Redhead Appreciation Day
• National Checkers Day
• Restless Legs Awareness Day

In addition, there are several multi-day events and observances that start or continue on September 23, 2023, such as National Alpaca Farm Days, National Surgical Technologists Week, and Animal Pain Awareness Month. However, there is no significant historical event or news mentioned in the search results that happened on this day.