Monaco’s national holiday dates back to 1857. It has been celebrated on 19 November since the reign of Prince Rainier III.
Among several attributes of a modern state introduced during the reign of Prince Charles III (a red-and-white national flag, diplomatic representation abroad) was the creation of a Monegasque national holiday.
In 1857, the young monarch decided that 4 November, his patron saint’s day, would become “Sovereign’s Day”.