Joshua 22:11-12

And the people of Israel heard it said, “Behold, the people of Reuben and the people of Gad and the half-tribe of Manasseh have built the altar at the frontier of the land of Canaan, in the region about the Jordan, on the side that belongs to the people of Israel.” And when the people of Israel heard of it, the whole assembly of the people of Israel gathered at Shiloh to make war against them.