Complex sentence: Jews were a major driving force of the town's commerce in the first half of the 19th century, founding a number of trading companies (some traded internationally), banking establishments, and serving as agents of the neighboring estates of Polish nobility (szlachta).
Split into simpler sentences: Jews were a major driving force of the town's commerce in the first half of the 19th century. They founded a number of trading companies (some traded internationally), banking establishments, served as agents of the neighboring estates of Polish nobility (szlachta).