Texas history can be divided into several major periods: prehistoric (up to the 16th century), Spanish colonial (1519-1821), Mexican national (1821-1836), Republic of Texas (1836-1845), U.S. statehood (1845-1861), Civil War and Reconstruction (1861-1876), and the Modern era (1876-present).
Prehistoric Texas is home to some of the oldest human remains in North America dating back over 10,000 years. The first Spanish explorers arrived in the early 16th century, but it wasn't until 1519 that began the process of conquest and colonization. For the next two hundred years, Texas was a part of the Spanish Empire, until Mexico won its independence in 1821.
The Mexican period was marked by conflict, as the Mexican government attempted to assert control over the largely unfamiliar territory of Texas. This led to the Texas Revolution of 1836, in which the settlers in Texas declared their independence and won a victory at the Battle of San Jacinto. Texas became its own country, the Republic of Texas, for nine years before being annexed by the United States in 1845.
As a U.S. state, Texas saw tremendous growth, especially in the second half of the 19th century. This was due in part to the expansion of the railroad, which made transportation and trade much easier. The state also became a major cattle-raising center, and agriculture grew to be a significant part of the economy. The Civil War and Reconstruction brought great changes to Texas, as slavery was abolished and the state was required to rebuild.
In the late 19th and early 20th centuries, Texas underwent a transformation as cities began to grow and new industries (such as oil) developed. This growth continued into the 21st century, making Texas one of the most populous and economically important states in the country.