Complex sentence: He quickly became a general and over the four years operated against the Spanish on behalf of both Venezuela and its neighbour New Granada; his successes included a difficult month-long fighting retreat through northern Venezuela to Barcelona in 1816.
Split into simpler sentences: He quickly became a general and over the four years operated against the Spanish on behalf of both Venezuela and its neighbour New Granada. He had some successes, including a month-long fighting retreat through northern Venezuela to Barcelona in 1816.