Adar is the sixth month of the civil year and the twelfth month of the ecclesiastical year on the Hebrew calendar, roughly corresponding to the month of March in the Gregorian calendar. It is a winter month of 29 days. The key Purim-related liberating wartime events and main mention of the month appear in the holy scripture of Esther 9, its last book. In leap years, it is preceded by a 30-day intercalary month named Adar Aleph and it is then itself called Adar Bet. Occasionally instead of Adar I and Adar II, "Adar" and "Ve'Adar" are used. Adar I and II occur during February–March on the Gregorian calendar. Based on a line in the Mishnah declaring that Purim must be celebrated in Adar II in a leap year, Adar I is considered the "extra" month. As a result, someone born in Adar during a non leap year would celebrate their birthday in Adar II during a leap year. However, someone born during either Adar in a leap year will celebrate their birthday during Adar in a non-leap year, except that someone born on 30 Adar I will celebrate their birthday on 1 Nisan in a non-leap year because Adar in a non-leap year has only 29 days. During the Second Temple period, there was a Jewish custom to make a public proclamation on the first day of the lunar month Adar, reminding the people that they are to prepare their annual monetary offering to the Temple treasury, known as the half-Shekel.
Holidays
7 Adar – 7th of Adar – some fast on this day in memory of the death of Moses 13 Adar – Fast of Esther – on 11 Adar when the 13th falls on Shabbat – ' 14 Adar – Purim 14 Adar I – Purim Katan 15 Adar – Shushan Purim – celebration of Purim in walled cities existing during the time of Joshua 17 Adar''' – Yom Adar celebration feast
In Jewish history
1 Adar – Plague of Darkness, the ninth plague upon the Egyptians. This started on the 1st of Adar, six weeks before the Exodus.
4 Adar – Maharam's body ransomed 14 years after his death by Alexander ben Shlomo Wimpfen.
4 Adar – Death of Rabbi Leib Sarah's, a disciple of the Rabbi Israel Baal Shem Tov. One of the "hidden tzaddikim," Rabbi Leib spent his life wandering from place to place to raise money for the ransoming of imprisoned Jews and the support of other hidden tzaddikim.
5 Adar – Lulianos and Paphos voluntarily gave themselves up to be killed, in order to save innocent Jewish lives in Laodicea.
7 Adar – Birth of Moses
7 Adar – Death of Moses
7 Adar – Death of Rebbe Isaac Taub of Kalov, founder of the Kalover Hasidic dynasty, and a student of Rabbi Leib Sarah's.
9 Adar – Academic dissension between Beit Hillel and Beit Shammai, erupted into a violent and destructive conflict over a vote on 18 legal matters leading to the death of 3,000 students. The day was later declared a fast day by the Shulchan Aruch, however, it was never observed as such.
13 Adar – War between Jews and their enemies in Persia.
13 Adar – Yom Nicanor – The Maccabees defeated Syrian general Nicanor, in a battle fought four years after the Maccabees' liberation of the Holy Land and the miracle of Hanukkah.
20 Adar – 'Purim Vinz': downfall of Vinzenz Fettmilch and triumphant return of the Jews of Frankfurt under Imperial protection. The day was established as a community Purim for generations and to this day the Washington Heights community does not recite Tachanun on this day.
24 Adar – The Blood Libel, the accusation that Jews murdered Christian children for their blood, declared false by Czar Alexander I. Nevertheless, nearly a hundred years later the accusation was officially leveled against Mendel Beilis in Kiev.
27 Adar – Death of Zedekiah in Babylonian captivity. Meroduch, Nebuchadnezzar's son and successor, freed him on the 27th of Adar, but Zedekiah died that same day.
28 Adar – Talmudic holiday to commemorate the rescinding of a Roman decree against Torah study, ritual circumcision, and keeping the Shabbat. The decree was revoked through the efforts of Rabbi Yehudah ben Shamu'a and his colleagues.
28 Adar – the Jews of Cairo were saved from the plot of Ahmad Pasha, who sought revenge against the Jewish minister Abraham de Castro who had informed Selim II of Ahmad's plan to cede from the Ottoman Empire. To this day, Adar 28th is considered the Purim of Cairo, with festivities including a special Megilah reading.