Richard Cassels, also known as Richard Castle, was an architect who ranks with Edward Lovett Pearce as one of the greatest architects working in Ireland in the 18th century. Cassels was born in 1690 in Kassel, Germany. Although German, his family were of French origin and descended from the French-Netherlandish 'Du Ry' family, famous for the many architects among their number. A cousin Simon Louis du Ry designed Schloss Wilhelmshöhe in Kassel.

Sir Edward Lovett Pearce was an Irish architect, and the chief exponent of Palladianism in Ireland. He is thought to have initially studied as an architect under his father's first cousin, Sir John Vanbrugh. He is best known for the Irish Houses of Parliament in Dublin, and his work on Castletown House. The architectural concepts he employed on both civic and private buildings were to change the face of architecture in Ireland. He could be described as the father of Irish Palladian architecture and Georgian Dublin.