5th Grade Version:
Stephen F. Austin, with a band of plucky yet determined pioneers, traveled to central Texas from (various versions Tennessee, Kentucky, or Virginia) in the 1820's to form a colony. This group was peaceful and happy until 1836, when mean ole' Santa Anna, the Mexican general, decided to kick them out. Leaders of the colony rallied, fought 3 quick yet decisive battles - the first, in Gonzales, famous for the flag the colonists made with a picture of a cannon on it that said "Come and Take It" ; the second, at the Alamo in San Antonio, where all the "Texans" who fought bravely were martyred, thus inspiring the motto " Remember the Alamo"; and the third, the Battle of San Jacinto, where General Sam Houston decisively routed the Mexican general Santa Ana during his afternoon siesta.
Grownup (short and overly simplified) Version:
European nations in the 15th, 16th, 17th and 18th centuries were engaged in competition for natural resources and land for expanding populations. This caused them to explore the world beyond Europe via water and land. While the battle between Spain and Britain in 1588 may have settled the dominance of the seas issue from the British point of view, pretty much everyone else just went about their business and carved up the Americas, Asia, Micro- and Polynesia, Africa, etc., as they could. Chief colonizers were from Britain, Spain, France, Portugal, and the Netherlands. Long-standing conflicts were established in local areas where European nations formed alliances and enemies - conflicts which exist to this day as the under-pinnings of our current geo-political system. Think Palestine. Rwanda. Vietnam.
Spain and Britain, and occasionally France, continued to fight to determine who would control North America (and the rest of the world.). The French and Indian War / Seven Year's War 1754-1763 and the American Revolution 1875-1783 established Britain, later the Americans, as the winner for the east coast of North America regions. Local wars continued the pattern of being smaller parts of a larger geopolitical power struggle. Spain had a stronghold in the southwest, central and South America. Some French explorers sailed up the Mississippi and into the Hudson Bay and Canada but nobody really cared. As populations grew, each side pushed towards the middle. Texas is where they met.
Texas, geographically, was originally part of New Spain (settled in 1690), and later Mexico (which succeeded from Spain in 1821 in its own revolution). The region was filled with ranches, farms, and small towns; it contained Spanish and native-speaking peoples of Spanish, Native American, and mixed descent. The current borders did not yet exist, and many families owned land on both sides of the Rio Grande River, which is the present day border with Mexico. Stephen F. Austin brought his colony to Texas legally, with a land grant originally awarded to his father. As more Anglo settlers from the USA joined the original "Old Three Hundred" families, the need for more land created conflict with Mexican overlords and prompted the Texas War for Independence. From the Texans' perspective, this war was immediate and personal; Texans felt they "won" but Mexico did not recognize that belief. From the United States of America's perspective, this conflict was part of a larger series of wars over territorial jurisdiction, known as "Manifest Destiny”: the War of 1812 (related tangentially to the Napoleonic Wars), the US- Mexican War of 1845-1847 (also involved in the USA’s internal dispute over free vs slave states), and the Spanish American War of 1896.
Texas, once admitted to the Union, was a slave state, but did not have as strong a farming/plantation economy as more eastern, southern states. It was so remote compared to the rest of the Confederacy that it took months for the slaves in Texas to find out about the Emancipation Proclamation and the end of the Civil War, which is why "Juneteenth" is a significant African-American holiday in Texas. Small farms and large ranches predominated, with railroads arriving to take cattle to markets in Chicago and St. Louis in the 1870-1880's. Oil was discovered in the 1920's. Military bases sprang up in the wake of WWII. NASA arrived in the 1960's. Recent cycles of boom and bust in the US economy have driven huge swells of population to Texas, searching for jobs and a better life. Throughout it all, the culture of Texas has encouraged a "hands off" attitude reminiscent of the old Wild Wild West - seen today in the Texas approach to taxes, government, and laws in general.