the brisk building activity was continued by philipp william's son and successor, margrave frederick william (1700-1771). initially under the tutelage of his uncle frederick (prussian king as "frederick i" since 1701) he ruled his dominions from 1731 onwards and began to develop schwedt into a country seat for the cadet line. in 1734 he had married his cousin princess sophia dorothea of prussia, a sister of king frederick the great. as he left no male heirs upon his death, philip william's youngest son, frederick henry (1709-1788) ruled as the last margrave of brandenburg-schwedt and developed schwedt into a cultural center. known for his numerous love affairs, his marriage with princess leopoldine marie of anhalt-dessau likewise produced no male descendants.