The Excommunication of William Marshall

William Marshall was known to many as the ‘greatest knight who ever lived’. When he married Isabel de Clare, the daughter of Strongbow and the granddaughter of King Diarmait Mac Murchada, William became the Earl of Pembroke and the owner of vast amounts of land in Wexford.

William and Isabel’s marriage was highly successful. They produced ten healthy children and founded many castles, churches, and towns throughout Leinster. However, William’s luck turned when he refused to return some land belonging to the church in Ferns.

As punishment for this, the Bishop of Ferns excommunicated William. This meant that he could not receive the holy sacraments, i.e., he could not confess his sins or receive the last rights. Despite this, William refused to give the land back to the Bishop, even on his deathbed.

William died in 1219, but this was not enough for the Bishop of Ferns. Furious that he still did not have the lands, he cursed the Marshal line promising that it would end with William’s childless sons. This seemed a bit ridiculous as William had five strapping and healthy lads to carry on the family name, but sure enough, over the following years, each of those healthy sons died without an heir.

William Marshal’s land and fortune were then split between his five healthy daughters and their children, who avoided the dreaded curse.


Ancient Connections the shared stories of Pembrokeshire and Wexford by Dr Gwilym Morus-Baird, Tara Clarke, Dr. Conor Ryan, Angharad Wynne and Neil Jackman.


Abarta Heritage, “The Excommunication of William Marshall,” Ancient Connections, accessed August 8, 2023,