Seventeenth of Tammuz

The Seventeenth of Tammuz (Biblical Hebrew: שִׁבְעָה עָשָׂר בְּתַמּוּז‎, Modern: Shiv'á Asár beTammúz, Tiberian (SBL): Šib̲ʿāʿāśār bəṯammuz)) is a Jewish fast day commemorating the breach of the walls of Jerusalem before the destruction of the Second Temple.

[2][3] It falls on the 17th day of the fourth Hebrew month of Tammuz and marks the beginning of The Three Weeks, a mourning period leading up to Tisha B'Av.

[4] The day also traditionally commemorates the destruction of the two tablets of the Ten Commandments and other historical calamities that befell the Jewish people on the same date.

It is customary among Ashkenazi Jews to refrain from listening to music, public entertainment, and haircuts on fast days, and on this occasion because it is also part of The Three Weeks (see below, Bein haMetzarim).

A Torah reading, a special prayer in the Amidah (Aneinu), and in many, but not all, Ashkenazic communities Avinu Malkenu are added at the morning Shacharit and afternoon Mincha services.

[14] The oldest extant reference to these days as Bein haMetzarim – which is also the first source for a special status of The Three Weeks – is found in Eikhah Rabbati 1.29 (Lamentations Rabbah, fourth century CE?).