It is not known precisely how much of Castletown is Galilei's work and how much Pearce's. If in Italy Pearce had been employed by Galilei and worked on the plans, then, as was the custom of the time, Pearce's work as an employee would have been credited to his master. Galilei was certainly responsible for devising the overall scheme of a principal centre mansion, flanked by colonnades leading to two service wings, in the true Palladian manner. Castletown was the first house in Ireland designed with this layout. The rigid symmetry of Castletown's classical facades, designed by Galilei was to be typical too of Pearce's later work.