Final answer:
Stephen F. Austin led the 300 families into Texas, making him responsible for settling the first significant colony of Anglo Americans in the region, which contributed to the cultural tensions leading to the Texas Revolution and the formation of the Republic of Texas.
Step-by-step explanation:
The person responsible for settling the first significant colony of Anglo Americans (US settlers) in Texas was Stephen F. Austin. Moses Austin, his father, initially obtained the land grant, but it was Stephen F. Austin who fulfilled his father's plans by leading 300 families into Texas in 1821. As a result of these settlements and the subsequent influx of American settlers, tensions grew between the American settlers—who were typically slave owners and religiously distinct from the Roman Catholic Mexicans—and the Mexican government. These tensions eventually led to the Texas Revolution and the creation of the Republic of Texas in 1836.