Jews around the world are observing the Fast of Gedaliah from before sunrise until after sundown Wednesday, in memory of the assassination of Gedalia ben Akhikam, governor of the Land of Israel for a short period following the destruction of the First Temple in 586 B.C.E (some say the year was 422).
Gedaliah's killing spelled the end of the small remnant of a Jewish community that remained in the Holy Land after the Temple's destruction. The Babylonians exiled the Jews of Judea in two stages (the ten tribes had been exiled by Assyria in the 8th century B.C.E.), first taking the professionals and wealthy to Babylon several years prior to the siege of Jerusalem and then leaving only a small number in the land after the Temple's destruction. Upon hearing of Gedaliah's appoitment, however, Jews who had fled to neighboring lands began to return and tend their vineyards and fields once again, in a small renaissance of Jewish life.
The nearby king of Ammon saw this negatively and persuaded one of Gedaliah's entourage, Yishmael ben Netanya, to assassinate him. Although warned, Gedaliah dismissed his friend Yokhanan ben Kereah's words as slander, and was murdered, along with those around him, including Babylonian supervising officials. The remaining Jews fled to Egypt and the short period of autonomy ended. The Prophet Jeremiah, who tells the story in Jeremiah 40, did not succeed in persuading the Jews who survived to stay.
The Talmud in Tractate Rosh Hashannah 18b takes up the question of how this fast compares with the other three mentioned in the Book of Zechariah, which are connected with actual destruction of the Temple or danger to the Jewish people -- the Fast of the Third, the Fourth and the Tenth months, commemorating the breach of the wall, the pillage of the city and the actual destruction of the Temple, as well as to the Fast of Esther - and makes the following declaration: “... The Fast of the Seventh Month is the Third of Tishrei, when Gedaliah was assassinated. And who killed him? Yishmael ben Netanya was the murderer – to teach you that the death of the righteous is equal to the burning of the House of G-d...”
The fast in Israel began at 4:51 a.m. and ends at 7:01 p.m. in Jerusalem and although some opinions are that he was killed on Rosh Hashannah itself, the fast is kept on the day after the New Year holiday, unless that falls on the Sabbath, in which case it is kept on Sunday..
For more about this fast day, click here