Always observed on the ninth day of the month of Av, hence Tisha (ninth) b’Av (in the month of Av) on the Jewish calendar, Tisha b’Av is a full day of deep, deep mourning, commemorating the destruction of the First Temple in 586 BC by the Babylonian king Nebuchadnezzar and the Second Temple by the Roman emperor Titus in 70 AD. Among many other calamities, this date also marks the expulsion of Jews from England, France, and Spain over a period of roughly 200 years.