Complex sentence: In the 1950s, all the neighborhoods south of Atlantic Avenue and west of Hoyt Street were called South Brooklyn, which derived its name from being south of the original town of Brooklyn (now Brooklyn Heights) which had been settled by the Dutch.
Split into simpler sentences: In the 1950s, all the neighborhoods south of Atlantic Avenue and west of Hoyt Street were called South Brooklyn. The area derived its name from being south of the original town of Brooklyn (now Brooklyn Heights) settled by the Dutch.