The medieval history of Enniscorthy Castle begins in the early days of the Anglo-Norman invasion of Ireland. Leader of this invasion, Strongbow, granted the lands of the Duffry which encompasses Enniscorthy to trusted knight Robert de Quency. De Quency however died in battle shortly after gaining his new lands which were then passed down to his infant daughter Maud who could regain her lands once she came of age. In the meantime guardianship of the Duffry was in control of a man name Raymond le Gros.
Le Gros would have constructed the first defensive structure on the site in the form of an earthen and timber “Motte and Bailey” castle. Around 1190 Maud de Quency married Philip de Prendergast and the couple regained the lands of the Duffry and constructed the first stone Castle on the site. For the following centuries and decades Enniscorthy Castle remained in ownership of the decadents of the Anglo- Normans until the Gaelic Irish revival in the late 1300’s.
In the 1370’s Gaelic Irish chief Art MacMurrough Kavanagh retook the Castle by force following which the Castle remained in his family’s ownership until they were finally surrendered in the 1530’s. For the next 50 years Enniscorthy Castle remained in a ruined condition until the arrival of Sir Henry Wallop who rebuilt the Castle for military use upon its existing foundations. Wallop also defeated the last of the Gaelic Irish resistance in the locality which meant that Enniscorthy Town could be made into a plantation town in the 1620’s. It was at this stage that the town began to grow and expand rapidly.