Today, October 2nd 2019, is the Fast of Gedaliah. This day is the third day of Tishrei, and is observed by Jewish people by fasting from dawn until dusk.
This day is in honor of a Judean leader named Gedaliah. Before he was a leader, there were only a few Jews remaining in Israel. Hope seemed lost, but then Jeremiah was allowed to return to Israel from exile. The Babylonian king also appointed a new leader of the Jewish people in Israel: Gedaliah. Gedaliah and Jeremiah brought hope, and many Jews traveled back to Israel. When things had seemed to turn around for the Jews, Gedaliah received a warning that an assassin was coming for him. This assassin was Ishmael ben Nethaniah, and Gedaliah did not believe that one of his own people would assassinate him. Ishmael came to visit for a meal, assumed to be for Rosh Hashana, and Gedaliah believed that this was a good sign. He believed that they are on the same side. However, in the middle of the meal, Ishmael killed Gedaliah. Ishmael and his men also killed everyone else at this meal. The Jewish people were left without a leader. This caused Jews to flee to Eygpt, and the autonomy of Jewish people in Israel was further pushed into history.
It is thought that Gedaliah was killed on the first day of the year, but as Rosh Hashana cannot be a day of fasting, Gedaliah is observed on the 3rd day of Tishrei.