Complex sentence: After the Seminole Nation agreed to the Reconstruction Treaty of 1866, there was a period of friction due to the U.S. government's recognition of Big John Chupco as the Chief of the Seminole, although the majority of the tribe followed the leadership of John Jumper.
Split into simpler sentences: After the Seminole Nation agreed to the Reconstruction Treaty of 1866, there was a period of friction due to the U.S. government's recognition of Big John Chupco as the Chief of the Seminole. But, the majority of the tribe followed the leadership of John Jumper.