william's widow, amalie elisabeth von hanau-münzenberg, served as regent for her son william vi, landgrave of hesse-kassel until he came of age in 1650. under her leadership many of the lands lost by her father-in-law and husband were regained through various foreign alliances and battles. in 1650, william's son, william vi, began his rule as landgrave, and continued the hesse-kassel line, which almost perished under maurice and william v.