Why did tecumseh bring together many american indian tribes?

He gathered a large group of tribes to fight the Americans.  He opposed the flow of settlers who were taking tribal lands away from Native Americans.  He later formed an alliance with the British during the War of 1812 to stop them from taking their land.  He was killed in the Battle of the Thames later on.

the  wilmot proviso  was designed to eliminate  slavery  within the  landacquired as a result of the mexican war (1846-48). fearing the addition of a pro-slave territory, pennsylvania congressman david  wilmot proposedhis amendment to the bill.