February 24:
A.D. 1208: Traditional date for St. Francis' reception of his vocation in a chapel outside of Assisi.
A.D. 1510: Pope Julius II excommunicates the Republic of Venice.
A whole republic...I guess they made him mad. :D
A.D. 1582: Pope Gregory XIII announces the new calendar (the Gregorian and modern calendar) as a replacement of the less accurate Julian calendar.