It is customarily considered as being the date of martyrdom or death of the Saint, thus celebrating their welcoming feast into Heaven.
April 23 is the Catholic feast day of Saint George.
Yes, that's why it is called St. Patrick's Day.
March 17 is the feast of St. Patrick.
Hercules is not a saint and has no feast day.
The feast day of Saint Valentine of Rome is on February 14. That is why it is called Valentine's Day.
Feast of the Assumption of the Blessed Virgin Mary - this is a major feast day
The feast day of Saint Apollonia of Alexandria is on February 9.
The feast day of Saint Anastasia of Sirmium is on December 25.
Her feast day is November 13.
Her feast day is on June 18.
His feast day is October 22.
Her feast day is October 6.