Numbers 16:1-2

Now Korah the son of Izhar, the son of Kohath, the son of Levi, with Dathan and Abiram the sons of Eliab, and On the son of Peleth, descendants of Reuben, took action, and they rose up [in rebellion] before Moses, together with some of the Israelites, two hundred and fifty leaders of the congregation chosen in the assembly, men of distinction.