Complex sentence: Attending the Convention of 1833 as representative for Nacogdoches, Houston emerged as a supporter of William Harris Wharton and his brother, who promoted independence from Mexico, the more radical position of the American settlers and Tejanos in Texas.
Split into simpler sentences: Attending the Convention of 1833 as representative for Nacogdoches, Houston emerged as a supporter of William Harris Wharton and his brother, who promoted independence from Mexico. This was the more radical position of the American settlers and Tejanos in Texas.