Complex sentence: Sowell participated in the Battle of Concepción and the Grass Fight and in December drove the army under General Martín Perfecto de Cos from Mexican Texas at the Siege of Bexar.
Split into simpler sentences: Sowell participated in the Battle of Concepción and the Grass Fight. In December the Texians drove the army under General Martín Perfecto de Cos from Mexican Texas at the Siege of Bexar.