Explore Around Dublin: Wicklow, Kildare and Meath The Wicklow coast The Wicklow Mountains County Kildare County Meath Share The oldest and largest Palladian country house in Ireland, Castletown is also one of the very finest. Its plain, grey but elegant facade, built in the style of a sixteenth-century Italian town palace, conceals a wealth of beautiful and fascinating interior detail. The house was built for William Conolly, son of a Donegal publican who, as legal adviser to William III, became the wealthiest man in Ireland from dealing in forfeited estates after the Battle of the Boyne. Though construction began in 1722, under first the Italian architect Alessandro Galilei and then his acquaintance, Edward Lovett Pearce, the interior was still unfinished at the time of Conolly’s death seven years later. A second phase of work began in 1758, when great-nephew Tom Conolly married the 15-year-old Lady Louisa Lennox, who set about altering and redecorating the house to restrained, Neoclassical designs by Sir William Chambers, the architect of the Casino at Marino, Dublin.