Hanukkah is an eight-day holiday commemorating the rededication of the Holy Temple in Jerusalem at the time of the Maccabean Revolt of the 2nd century BCE.
The festival is observed by the kindling of the lights of a nine-branched Menorah, or Hanukkiyah, one additional light on each night of the holiday, progressing to eight on the final night. An extra light called a shamash (Hebrew: "guard" or "servant") is also lit each night for the purpose of lighting the others, and is given a distinct location, usually above or below the rest.
Candles are placed in the Hanukkiyah beginning on the right, the direction in which we read Hebrew, and are lit from the left most candle first.
Although there was a difference of opinion between Rabbi Hillel and Rabbi Shammai regarding the lighting of the candles--Hillel suggested adding one additional candle each night while Shammai suggested beginning with eight and removing one each night--it was determined that we follow Hillel’s example.