 King John also died that year, and he also left an underage heir in King Henry III with a minority government set up in England.In 1217, Reginald de Braose of Brecon and Abergavenny, who had been allied to Llywelyn and married his daughter, Gwladus Ddu, was induced by the English crown to change sides.Llywelyn responded by invading his lands, first threatening Brecon, where the burgesses offered hostages for the payment of 100 marks, then heading for Swansea where Reginald de Braose met him to offer submission and to surrender the town.