Chanukah is one of the few Jewish holidays not mentioned in the Bible (hint, another is Purim!). The story of how Chanukah came to be is contained in the book of Maccabees 1 and 2, which are not part of the Jewish canon of the Hebrew Bible. The Talmud in tractate Shabbat also gives us some insight into the history and nature of Chanukah, including laws around rituals that we practice like the lighting of the Chanukiah. 

The events that inspired the Chanukah holiday took place during a particularly turbulent phase of Jewish history. Around 200 B.C.E, Judea, also known as the Land of Israel came under the rule of Antiochus III, the Seleucid king of Syria. At the beginning of his reign he was favorably disposed toward the Jews and accorded them some privileges. His son, Antiochus IV, proved less favorable, ancient sources recount that he outlawed the Jewish religion and ordered the Jews to worship Greek Gods. At the same time, the influence of the Hellenists (people who accepted idol-worship and the Greek way of life) was increasing. Yochanan, the High Priest at the time, tried to do all he could to push back on the Syrian-Greek influence. This led to internal strife between him and the Jewish Hellinists. 

Some modern historians suggest that this internal strife between those who had assimilated into the dominant culture that surrounded them, and those who were determined to impose Jewish laws and traditions is at the core of the Chanukah story. The traditionalists won out in the end, with the Hasmonean dynasty gaining control of the land of Israel and maintaining an independent Jewish kingdom for over a century.

Antiochus IV had enacted a series of harsh decrees against the Jews which eventually led to forcing them to serve Pagan gods. In 168 B.C.E, his soldiers entered Jerusalem, massacring thousands of people and desecrating the Second Temple. Mattityahu and his 5 sons, led by Judah who was known as the Macabee, a word composed of the initial letters of the four Hebrew words Mi Kamocha Ba’eilim Hashem, «Who is like You, O G‑d» led a revolt that lasted for 3 years. They eventually overcame Antiochus and his army and were able to liberate the city of Jerusalem. Later when they went to re-dedicate the Temple, they found one cruse of oil bearing the seal of the High Priest Yochanan. The oil was sufficient to light for one day but it miraculously lasted for eight. Shortly thereafter the Rabbis established the 8 day holiday of Chanukah to commemorate these two miracles and to celebrate the continuation of Jewish religious life which had been challenged both internally and externally.