Complex sentence: After the war, a Territorial Government was established as a component of the new Reconstruction Treaties signed with the various tribes that had sided with the Confederacy, and by 1871 the Federal Government dealt with tribes through statute.
Split into simpler sentences: After the war, a Territorial Government was established as a component of the new Reconstruction Treaties that were signed by the various tribes that had sided with the Confederacy. By 1871 the Federal Government dealt with tribes through statute.