In 1135, the twins were present at King Henry's deathbed. Robert's actions in the succession period are unknown, but he clearly supported his brother's decision to join the court of the new king Stephen before Easter 1136. During the first two years of the reign Robert is found in Normandy fighting rival claimants for his honor of Breteuil. Military action allowed him to add the castle of Pont St-Pierre to his Norman estates in June 1136 at the expense of one of his rivals. From the end of 1137 Robert and his brother were increasingly caught up in the politics of the court of King Stephen in England, where Waleran secured an ascendancy which lasted till the beginning of 1141. Robert participated in his brother's political coup against the king's justiciar, Roger of Salisbury (the Bishop of Salisbury).