Why would Tecumseh work for a confederation?

Tecumseh wanted to unite the Indian people to develop a confederation that would be an autonomous state for the Indians. He hoped this would stop White encroachment.

Explanation:

Tecumseh was a warrior chief from the Shawnee nation who was active in the War of 1812 and who tried to organize a Native American confederacy. He felt a confederacy would help to build an autonomous state for the Indians that would help to stop further white settlement in the Great Lakes region. Tecumseh believed that the Indian nations and tribes needs to cooperate to stop the encroachment from White settlers. He fought on the side of the British in the war of 1812 but was killed in battle. His dream of a confederation never materialized.

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.