Fast Of Tisha B'Av. It is considered the most important fast related to the. Tisha b'av starts at the time of sunset,.
The period begins on the 17th of the hebrew month of tammuz, a fast day that marks the day when the walls of jerusalem were breached by the romans in 69 ce. Tisha b’av (the fast of the ninth of av) is the darkest day on the jewish calendar, a day of communal mourning to commemorate the many tragedies that have.