Spain and subsequently Mexico controlled much of what is now the western United States until the Mexican–American War, including the entire state of Texas. After Texas joined the United States, the native Tejanos living in the state began culturally developing separately from their neighbors to the south, and remained culturally distinct from other Texans. Central to the evolution of early Tejano music was the blend of traditional Mexican forms such as mariachi and the corrido, and Continental European styles introduced by German and Czech settlers in the late 19th century. In particular, the accordion was adopted by Tejano folk musicians around the start of the 20th century, and it became a popular instrument for amateur musicians in Texas and Northern Mexico.