Complex sentence: Landowners John and Lieven Jansen and a group of loyal slaves resisted the attack and held off the advancing rebels with gunfire, thus allowing the Jansens to retreat to their waiting boat and escape to Durloe's Plantation.
Split into simpler sentences: Landowners John and Lieven Jansen and a group of loyal slaves resisted the attack and held off the advancing rebels with gunfire. The Jansens were able to retreat to their waiting boat and escape to Durloe's Plantation.