Complex sentence: In 1903 Dell moved with his family to Davenport, Iowa, which was then a liberal and cosmopolitan port city and center of trade with a thriving literary and intellectual scene.
Split into simpler sentences: In 1903 Dell moved with his family to Davenport, Iowa. At the time Davenport was a liberal and cosmopolitan port city and center of trade with a thriving literary and intellectual scene.