Philip was born about 1070 to 1073 in Bramber, Sussex, the son of William de Braose, 1st Lord of Bramber (d circa 1093/96) by his wife Eve de Boissey or Agnes de Saint Clare. William de Braose had participated in the Norman victory at the Battle of Hastings in support of William the Conqueror. He had been rewarded with the feudal barony of Bramber including lands in Sussex and smaller holdings in Dorset, Wiltshire, Berkshire and Surrey.
Philip as heir consolidated his paternal lands, and expanded them. In 1096 he confirmed his father"s gifts to the Abbey of Saint Florent. Philip de Braose conquered the Welsh borderlands at Builth and New Radnor and established new Norman lordships over them.
At Builth, he constructed a Motte and Bailey fortification at the site where King Edward I later built Builth Castle in the 13th century.
He seems to have gone on the First Crusade in 1103. He died between 1131 and 1139, possibly in 1134 on crusade in the Levant.
