 In the early Middle Ages the territory of Hessengau, named after the Germanic Chatti tribes, formed the northern part of the German stem duchy of Franconia, along with the adjacent Lahngau.Upon the extinction of the ducal Conradines, these Rhenish Franconian counties were gradually acquired by Landgrave Louis I of Thuringia and his successors.After the War of the Thuringian Succession upon the death of Landgrave Henry Raspe in 1247, his niece Duchess Sophia of Brabant secured the Hessian possessions for her minor son Henry the Child.