Numbers 16:1-2

Then Korah the son of Izhar, the son of Kohath, the son of Levi, decided to speak against Moses. Eliab's sons, Dathan and Abiram, and Peleth's son, On, who were descendants of Reuben, were with him. Together with 250 leaders of the Israelites, they all turned against Moses. Those were famous men that the people had chosen as their leaders.