 These countships were partitioned between themselves many times over the next 700 years.The House of Isenburg was an old aristocratic family of medieval Germany, named after the castle of Isenburg in Rhineland-Palatinate.Occasionally referred to as the House of Rommersdorf before the 12th century, the house originated in the Hessian comitatus of the Niederlahngau in the 10th century.