Complex sentence: Pill Priory was established by the Roche family of the Barony and Roch Castle, Pembrokeshire and was founded within a few years of St Dogmaels, the founder was Adam de la Roche, who would of necessity be a descendant of Godebert de Fleming.
Split into simpler sentences: Pill Priory was established by the Roche family of the Barony and Roch Castle, Pembrokeshire and was founded within a few years of St Dogmaels. The founder was Adam de la Roche, a descendant of Godebert de Fleming.