Question:

When did Chanukah become an official Jewish holiday? I know that the Holy Temple was reclaimed by the Maccabees in 139 BCE, but when did Jews start kindling Chanukah lights, eating latkes and playing dreidel?

Answer:

When the miracle of the oil occurred in 139 BCE, the Jews celebrated. The rabbis then proclaimed that these eight days should become an annual holiday on the Jewish calendar. So on the next year, 138 BCE, Chanukah was celebrated for the first time—complete with the lighting of the Chanukah Menorah.

As for eating latkes and playing dreidel, it's less clear when these traditions began. But both these customs are certainly many centuries old, and have become venerated customs practiced by Jews worldwide.

Chaya Sarah Silberberg,
Chabad.org