Betar, also spelled Beitar, Bethar or Bether, was an ancient Jewish town in the Judean Mountains. Continuously inhabited since the Iron Age, it was the last standing stronghold of the Bar Kokhba revolt, and was destroyed by the Imperial Roman Army under Hadrian in 135 CE.
Walls of the Betar fortress.
Av is the eleventh month of the civil year and the fifth month of the ecclesiastical year on the Hebrew calendar. It is a month of 30 days, and usually occurs in July–August on the Gregorian calendar.
Francesco Hayez, The Second Temple in flames, 1867. The 9th of Av, Tisha B'Av, is a fast commemorating what has been called the saddest day in Jewish history, which is when the Holy Temple was set aflame.