What are the motifs in Texas by James A. Michener?

Historical Significance is a recurring idea in the book. Michener discusses the major events in the book. The obvious events are the clashes with the Indians, the war for independence, the Mexican War, and the Civil War. Michener examines these events within the framework of the novel. But there are also lesser events that are of historical significance such as the movement of people. People moved in and around Texas when it was still part of Mexico.