Complex sentence: His third marriage was with Margaret Chedworth (1436-1494), daughter of Sir John Chedworth and Margaret Bowett, and widow of Nicholas Wyfold (1420-1456), Lord Mayor of London.
Split into simpler sentences: His third marriage was with Lady Margaret Chedworth (1436-1494), daughter of Sir John Chedworth and Margaret Bowett. Margaret was the widow of Nicholas Wyfold (1420-1456), Lord Mayor of London.