B'midbar (Num) 16:1-2

Now Korach the son of Yitz’har, the son of K’hat, the son of Levi, along with Datan and Aviram, the sons of Eli’av, and On, the son of Pelet, descendants of Re’uven, took men and rebelled against Moshe. Siding with them were 250 men of Isra’el, leaders of the community, key members of the council, men of reputation.