German-born architect who in the 1720s settled in Ireland under the aegis of Sir Gustavus Hume, Bt., and Pearce (from whom he was to inherit a considerable practice). Reared in the Baroque tradition, he became a fine exponent of Palladianism. Cassels's first independent work is the Printing House, Trinity College, Dublin, with a Doric temple-front, but his most important Dublin buildings are Tyrone House, Marlborough Street (1740—which incorporates his favourite Palladian motif of a serliana surmounted by a blind arch), and Leinster House (1745–7), probably inspired by Burlington House in London. Outside Dublin, Ballyhaise, Co. Cavan (1733), is one of Cassels's earliest country-houses, and has two important features: a stone frontispiece with superimposed Doric and Ionic pilasters; and a semi-elliptical projection or bow on the rear elevation, suggesting Continental Baroque exemplars, and indicating the elliptical saloon behind (an innovation for Ireland that anticipated the English fashion for elliptical saloons by some four decades). Russborough, Blessington, Co. Wicklow (1741–50), is one of the most mature of Irish Palladian buildings, with exquisite Baroque and Rococo plaster-work inside.
Bence-Jones (1988);M. Craig (1969, 1982);Glin (1964);McParland (2001);Summerson (ed.) (1993)