In the later medieval centuries the Hospitallers’ estates in Wales were among the most extensive of any religious corporation there. In 1535, just before the dissolution of the monasteries, the commandery at Slebech was the third richest monastic house in Wales, after the Cistercian abbeys at Tintern and Valle Crucis. The next richest house after Slebech was another Cistercian house, Margam Abbey, followed by the Benedictine priory at Abergavenny. ² Slebech was also wealthy by comparison with other Hospitaller houses in England and Wales. In 1338 it received the largest income of any Hospitaller house in England and Wales, apart from the main house at Clerkenwell just outside London, ³ while in 1535 it had the fourth highest net value of the Hospitallers’ twenty-two houses in England and Wales, after Clerkenwell, Buckland and Ribston. ⁴ With such comparative wealth, we might expect the Hospitallers to have held great authority and power in Wales, and their Welsh property to have been very significant within the Order.