What is the theme in Texas by James A. Michener?

Opportunity is a dominant theme of the book. Many people came to Texas for the opportunities that it offered. In the early days, Texas was the place where people could start new lives. The early settlers could receive free land if they were Catholic and married. The work was hard and the risks were great, but most liked the lives they carved out for themselves. Very few chose to return to the places they came from.