The holiday commemorates the rededication of the holy Temple in Jerusalem after the Jews' 165 B.C.E. victory over the Hellenist Syrians. Antiochus, the Greek King of Syria, outlawed Jewish rituals and ordered the Jews to worship Greek gods.
In 168 B.C.E. the Jews' holy Temple was seized and dedicated to the worship of Zeus.
Some Jews were afraid of the Greek soldiers and obeyed them, but most were angry and decided to fight back.
The fighting began in Modiin, a village not far from Jerusalem. A Greek officer and soldiers assembled the villagers, asking them to bow to an idol and eat the flesh of a pig, activities forbidden to Jews. The officer asked Mattathias, a Jewish High Priest, to take part in the ceremony. He refused, and another villager stepped forward and offered to do it instead.
Mattathias became outraged, took out his sword and killed the man, then killed the officer. His five sons and the other villagers then attacked and killed the soldiers. Mattathias' family went into hiding in the nearby mountains, where many other Jews who wanted to fight the Greeks joined them. They attacked the Greek soldiers whenever possible.
Judah Maccabee and his soldiers went to the holy Temple, and were saddened that many things were missing or broken, including the golden menorah. They cleaned and repaired the Temple, and when they were finished, they decided to have a big dedication ceremony.
For the celebration, the Maccabees wanted to light the menorah. They looked everywhere for oil, and found a small flask that contained only enough oil to light the menorah for one day. Miraculously, the oil lasted for eight days. This gave them enough time to obtain new oil to keep the menorah lit.
Today Jews celebrate Hanukkah for eight days by lighting candles in a menorah every night, thus commemorating the eight-day miracle.