 In 1324 Alexander de Bicknor built or restored an archiepiscopal manor at Tallaght, which was fortified later to protect the English in Dublin from the attacks of the O'Byrnes.During the Dissolution of the monasteries at the Reformation, the Protestant archbishops took charge of Tallaght.However, in 1812, the castle was sold to the Dominicans, who erected a Roman Catholic novitiate and church there.