An ancient and unique source documenting the Yomim Tovim of the Jewish people is Megillas Taanis. Megillas Taanis is a relatively short Megillah which, to all appearances, seems to have been written over the course of several generations. In it are recorded thirty-six occasions which were of a positive nature for the Jewish people. Megillas Taanis partially preceded the writing of the Mishnah. Chazal explain that despite the fact that it preceded the writing of the Mishnah by Rabi Yehudah haNasi, it was not incorporated into the body of the recorded Oral Law, since it does not come to teach any of the laws of the Torah. Nevertheless, it was important to transcribe its contents, in order that the coming generations should know upon which days salvation had come to the Jewish people, and so that none should fast on these days.

In the Talmud Bavli, maseches Shabbos, a Baraisa asks; “Who wrote Megillas Taanis?” The Tanna then answers “It was Chanania ben Chizkiya and his group, to whom the sufferings were beloved.” Rabbeinu Shlomo Yitzchaki – Rashi – explains as follows; “the sufferings were beloved – when the miracle became apparent to them, it was beloved to them to remember it and to praise Hakadosh Baruch Hu, and they recorded the days upon which the miracles occurred in order to make them a Yom Tov, upon which one was not to fast.” Despite this, at the end of Megillas Taanis itself, it is written; “And who wrote Megillas Taanis? It was the group of Rabi Eliezer ben Chanania ben Chizkiya ben Garon who wrote Megillas Taanis.”

In order to resolve this apparent contradiction between the words of the Baraisa and those of the Megillah itself, Chazal explained that the Megillah was written over the course of several generations. The beginning was written by Chanania ben Chizkiya and his group, and it was completed by Eliezer, his son. As a proof to their conclusion, Tosefos inform us that Chanania and his group lived in the times of Shammai and Hillel – and yet in the Megillah there is a miracle recorded that occurred on the 28th of Adar in the times of Rabi Yehudah ben Shamua – who was a talmid of Rabi Meir who was himself a talmid of Beis Shammai. Therefore, if this is the case, it must be that the Megillah was written over the course of several generations, and so the words of the Baraisa in maseches Shabbos refer to the beginning of the writing of the Megillah, and those at the conclusion of the Megillah itself can be attributed to the time of the conclusion of the writing.

It appears that even after Megillas Taanis was completed, several additions were made over the coming generations. There are those who attribute the final chapter of the Megillah or at least the bulk of it to the period of the Gaonim.
Already during the period of the Tannaim and continuing until our times, it was not the common practice to observe the days ennumerated in Megillas Taanis as festive occasions, and the Megillah was effectively abolished as a practical guide.

One of the reasons for this development was brought by Chazal – the fact that a number of the occurrences mentioned in the Megillah were linked to the offering of sacrifices in the Beis haMikdash, and after, due to our many sins, the Beis haMikdash was destroyed, the reason for our rejoicing on those days disappeared, and therefore the Megillah no longer had practical implications. Another reason which is brought in the Megillah itself, towards the end is; “And why was it written? Because [they, who wrote the Megillah,] were not accustomed to suffering and their times were not filled with suffering – but during our times, when we are used to suffering and experience it constantly, if all the seas were ink, and all the reeds were quills and all the people were scribes, it would still not suffice to transcribe all the sufferings which befall us each and every year.” This reason is also brought in other sources in Chazal – that owing to the great sufferings brought on by the bitter golus, the Megillah was abolished. Despite it being abolished, however, two festivals did remain with us until the present day – the days of Purim and the days commemorating the miracle of Chanukah.

The events recorded in Megillas Taanis are divided into two categories. There are those days upon which it was forbidden to fast, which are recorded without further elaboration – and there are other days on which eulogies were also forbidden, which are mentioned with the language “it is sufficient not to recite eulogies.”

The events recorded in the Megillah present an historical account of several periods in time. The earlier events date back to the time of Ezra and Nechemiah and the return to Eretz Yisrael after the first exile. Among the events recounted here are the day on which the walls of Yerushalayim were consecrated, and the days of Purim. Other events date back to the period of the Chashmonaim, including the festival of Chanukah. Later events relate to the period of Roman rule over Eretz Yisrael, before and after the destruction of the second Beis Hamikdash.

Many of the events recounted in Megillas Taanis relate to victories of the Perushim (often called ‘Pharisees’ in English) over the Tzadukim (often called ‘Sadducees’). The Perushim were the Jews who adhered to the eternal traditions of the Jewish people who fulfilled the mitzvos of the Written and Oral Laws in the manner of all previous generations. Opposing them were the Tzadukim and Baitusim, who denied the legitimacy of the Oral Law and only followed the words of the Written Law, without delving into them beyond the simple interpretation. The Tzadukim and the Baitusim were the talmidim and the perpetuators of the derech of Tzadok and Baitus, who were talmidim of Antigonos ish Socho. Antigonos ish Socho taught his talmidim, “Do not be as servants who serve their master in order to receive a reward – instead be as servants who serve their master not in order to receive a reward.” Tzadok and Baitus both misinterpreted the words of their teacher and went on to deny the validity of the Oral Law.

Many bitter disputes took place between the Tzadukim and the Perushim, especially after the Roman conquest when the Tzadukim purchased for themselves the right to appoint whomever they wished as Kohen Gadol, regardless of his suitability for the position, causing the entire Temple service to fall into disrepute. One of the most famous disputes between the Perushim and the Tzadukim was on the matter of Sefiras haOmer. According to the words of Chazal, which explain the words of the pesukim, it emerges that the intention of the Torah when it states, “And you shall count for yourselves from the day after the Shabbos,” was that the counting of the Omer should commence on the day after the first Yom Tov of Pesach, as Yom Tov is referred to as Shabbos – and Shabbos itself is referred to as ‘Shabbos Shabbaton’. The Tzadukim rejected this interpretation of Chazal, and argued that the count should rather commence on the day after the first Shabbos that falls following the first Yom Tov of Pesach. On every day upon which the Perushim emerged victorious over the Tzadukim on any one of their disputes, the day was established in Megillas Taanis as a Yom Tov.

The following are the Yomim Tovim that are recorded in Megillas Taanis:

- In the month of Nissan, from Rosh Chodesh until the 8th of Nissan – these days have been established as Yomim Tovim, due to the victory of the Perushim over the Tzadukim on the matter of the Korban Tamid. The Baitusim had said that the Korban Tamid was a sacrifice for the individual, as it says; “The one sheep…”, but the Perushim disagreed and said that it is a communal sacrifice, as it says; “Command the children of Yisrael…” The Tzadukim argued their point for these eight days and were eventually defeated – therefore, these days were established as Yomim Tovim.

- From the 8th of Nissan until after the seven days of Pesach, a ban was imposed on fasting, because of the defeat of the Tzadukim at the hands of the Perushim on the matter of their dispute on the offering of the Korban haOmer and the Sefiras haOmer, which centred on their differing interpretations of the words “mimacharas haShabbos.”

- In the month of Iyar on the 7th of the month, eulogies were not permitted, since on that day, the walls of Yerushalayim were consecrated during the period of the return to Zion (Eretz Yisrael) during the days of Ezra and Nechemiah. In addition, this was the day upon which the doors to the walls were erected, during the Chashmonaim period.

- On the 14th of Iyar, which is Pesach Sheni, as is mentioned in the Torah, it is forbidden to fast and deliver eulogies.

- On the 23rd of Iyar a Yom Tov was established, since on that day, the bnei Chikra left Ir David – these were people who had been harrassing the Jews of nearby Yerushalayim.

- On the 27th of Iyar, the Chashmonaim gained the upper hand against the Greeks, and abolished their decrees commanding the Jews to hang wreaths of roses dedicated to idol worship on the entranceways to their homes and stores, and to write on the horns of an ox that the Jews no longer had a portion in the G-d of Yisrael, chas v’shalom.

- In the month of Sivan, on the 14th of the month, the fortress of Tzur was captured by the Chashmonaim and the Edomites were expelled from there, the fortress then returning to Jewish hands.

- On the 15th and 16th of Iyar, the Chashmonaim expelled the Edomites of Beit She’an and the valley, who had settled there under the Greeks, and this area returned to Jewish hands.

- On the 25th of Sivan, the tax collectors left Yehudah. These were Africans who had argued before Alexander of Macedonia that Eretz Cana’an was rightfully theirs, since they were called Cana’anim. Geviha ben Pasisa went to debate with them and argued that the Africans were really slaves, as it says of Cana’an; “A slave of slaves he shall be to his brothers.” Following this, the Africans fled, leaving behind their fields and crops, and this day was fixed as a Yom Tov.

- In the month of Tammuz, on the 14th of the month, it was forbidden to fast and deliver eulogies, since on that day, the ‘Book of Decrees’ of the Tzadukim was abolished. The book had ruled according to a literal and extreme interpretation of the punishments recorded in the Torah – ‘an eye for an eye’ etc., without taking into account the explanations of Chazal on these verses.

- In the month of Av, on the 15th of the month, fasting and delivering eulogies was forbidden, since on that day, the wood sacrifice had been brought to the Beis haMikdash, and all those who had donated items to the sanctuary, even the tiniest amount of wood, would rejoice greatly on that day.

- On the 24th of Av a Yom Tov was established, since on this day, the Chashmona’im succeeded in abolishing the decrees of the Greeks, which were supported by the Tzadukim. From then onwards, the laws of the Torah were once again those that governed Eretz Yisrael.

- In the month of Ellul, on the 7th of the month, the walls of Yerushalayim were consecrated – it appears that this dedication of the walls was during the times of the Chashmonaim, who repaired the breaches that the Greeks had made in the walls. It was only later, during the month of Iyar, that the gates which had been broken down were repaired by the Chashmonaim.

- On the 17th of Ellul, the Roman inhabitants of Yerushalayim, who had been settled there by the Greeks, left the city. These Romans had harrassed the Jews, and it was in relation to them that the story of Yehudis, the daughter of Mattisyahu haChashmonai, had occurred. On this day, the Chashmonaim defeated these peoples and drove them away, and so it was established as a Yom Tov.

- On the 22nd of Ellul, the proper rule of the Torah Beis Din returned, and the members of the apostate Beis Din who had transgressed the laws of the Torah, were killed.

- In the month of Tishrei, on the 3rd of the month, a decree was enacted forbidding the recording of the name of Hashem on official documents. The writing of the holy name on documents had been instituted by the Chashmonaim against the Greeks, but it had led to the disgrace of the honour of Hashem, since once the document had fulfilled its purpose, it was torn up. Therefore, the day upon which the writing of Hashem’s holy Name was forbidden was established as a Yom Tov.

- In the month of Marcheshvan, on the 23rd of the month, the Chashmonaim hid away the screen in the sanctuary that the Greeks had used to commit abominations in the Beis haMikdash, in order to defile it.

- On the 25th of Marcheshvan, the walls of Shomron were breached. There had lived the Kusim, who had caused much trouble for the Jews.

- On the 27th of Marcheshvan, the Perushim defeated the Tzadukim in their debate over the eating of the Mincha animal offering. The Kusim had argued that the Mincha offering should be eaten, and that it was not offered on the Mizbeyach – whereas the Perushim argued that the Mincha offering should indeed be offered as a sacrifice to be burned for Hashem, on the Mizbeyach. On this day, upon which the Perushim defeated the Tzadukim on this matter, the Mincha offering resumed being offered as a burnt sacrifice on the altar.

- In the month of Kislev, on the 3rd of the month, the graven images that had been set up by the Greeks in the courtyard of the Beis haMikdash, were removed by the Chashmonaim, and therefore this day was established as a Yom Tov.

- The 7th of Kislev was fixed as a Yom Tov since on that day King Hordos (Herod) died, who had persecuted talmidei chachomim and killed many of them. It is a cause for great rejoicing before Hakadosh Baruch Hu when evildoers pass from this world.

- The 21st of Kislev was established as a Yom Tov upon which fasting and giving eulogies was forbidden. It was on this day that the Kusim went to Alexander of Macedonia with the slander against the Jews that they had rebelled against him. When Alexander of Macedonia reached Yerushalayim, Shimon haTzaddik went out to greet him, dressed in his garments as Kohen Gadol. Alexander of Macedonia then bowed down before him, saying that his image appeared before him in all his battles, leading him to victory. After this, the Jews tied the Kusim to the tails of their horses and dragged them to Har Gerizim, where their sanctuary was located, and they ploughed over the sanctuary and sowed it with seeds. Therefore, this day was established as a Yom Tov and called ‘The day of Har Gerizim’.

- The 25th of Kislev is the first day of the festival of Chanukah which is celebrated for eight days. On this day the Chashmonaim defeated the Greeks. They only found one tiny flask of pure oil with the seal of the Kohen Gadol intact, with which to light the menorah in the Beis haMikdash. The flask contained oil sufficient only for one day of burning, but a miracle occurred and it burned for eight days, until new oil could be extracted from a fresh pressing of olives. The days of Chanukah are one of the two incidences of Yomim Tovim in the Megillah that have been preserved to the present day.

- In the month of Teves, on the 28th of the month, the Sanhedrin of Tzadukim died out in the times of King Yannai, and Shimon ben Shotach appointed in their place a Sanhedrin of seventy-one chachomim from the ranks of the Perushim. In the merit of this event, the day was declared a Yom Tov.

- In the month of Shevat, on the 2nd of the month, a Yom Tov was established and fasting and eulogies are not permitted, since on this day, King Yannai died, who had murdered many chachomim and confined them to prison, so that the Jews should not be able to rejoice when he became ill. When he died, the world was rid of this evil man and the imprisoned chachomim were released.

- On the 22nd of Shevat the decree of the evil Kasgalges, who had commanded that an idol be set up in the sanctuary of the Beis haMikdash, was abolished. When his emissary set out with the idol in his hand, all Am Yisrael davened that Hakadosh Baruch Hu should abolish the decree – and so it was – when the emissary was yet on his way, Kasgalges died and the decree was abolished. At that moment, Shimon haTzaddik heard a bas kol coming from the Kodesh haKadoshim, proclaiming that “The the plot of the wicked one to bring [an idol] into the sanctuary has been abolished, Kasgalges has been killed and his decree has been abolished.” This day was therefore declared a Yom Tov upon which one is not to fast or deliver eulogies.

- On the 28th of Shevat Antiochus left Yerushalayim following evil tidings he had received, and he returned to his hometown. This gave a respite to the Jews of Eretz Yisrael from his decrees, and so this day was declared to be a Yom Tov.

- In the month of Adar, on the 8th and 9th of the month, prayers for rain are offered, and one is not to fast upon these days.

- On the 12th of Adar is ‘Yom Turainus’. On this day, Turainus killed Lulinus and Pappus at Ludkia. These two had rescued many Jews from the foreign government, and their murder was accounted as a martyrdom, for which Turainus was punished from Heaven – the officials in Rome had him killed by splitting his head open.

- On the 13th of Adar is ‘Yom Nikanor’. This particular Nikanor was a cruel Greek king who would mock and curse Hashem every day, and awaited an opportunity to destroy the Beis haMikdash himself. On the 13th of Adar the Chashmonaim launched an attack against Nikanor and his soldiers, and they were all killed, the soldiers together with their king.

- The 14th and 15th of Adar are the days of Purim, when miracles were performed for Mordechai the Jew and Queen Esther in Shushan haBirah. The decree of the evil Haman haAgagi was overcome and he together with his sons was hanged from a tree. The Jews fought against their enemies and emerged victorious – these two days were when the battles finally ceased, over the country and in Shushan haBirah respectively. These two days mark the second set of events recorded in Megillas Taanis which are still celebrated today – according to Chazal, the days of Purim will never be abolished.

- On the 16th of Adar a Yom Tov was established, since on this day, the Jews of Yerushalayim were permitted to rebuild the walls of the city which had been destroyed by the goyim.

- On the 17th of Adar a Yom Tov was established. When King Yannai killed many of the chachomim, others fled to Syria, and some of them stopped off in the land of Kalkis, where the goyim tried to have them killed. Hakadosh Baruch Hu performed a miracle for them and they were rescued – therefore, this day was declared a Yom Tov.

- On the 20th of Adar a miracle occurred to the Jewish people through Choni haMe’agel. After three years of drought, when no rain fell in Eretz Yisrael, the Jews turned to Choni haMe’agel, imploring him to offer up a prayer to Hashem for rain. Choni agreed to the request of his brothers, and he drew a circle in which he stood and davened for rain. His tefillah was accepted and on this day, rain began to fall – and so the day was declared a Yom Tov.

- On the 28th of Adar the Roman decree forbidding circumcision of newborn babies was rescinded. The Romans had also forbidden the observance of Shabbos and commanded the Jews to serve idols. On the advice of a Roman woman, Yehudah ben Shamua together with other chachomim, made protests at night until the decrees were abolished. The day upon which the decrees were abolished was established as a Yom Tov upon which fasting and eulogizing the dead was forbidden.

All these thirty-six days of Yamim Tovim are recorded in Megillas Taanis – all that remains of them today are the festivals of Chanukah and Purim.