History
The early history of the house is inextricably linked with the adjacent church of St. Nidan's. In Medieval times the parish of Llanidan and its rectory became annexed to the Augustinian Priory of Beddgelert. Records have been lost through fire and the date of this transfer is unknown, the earliest reference to Llanidan being in 1342 concerning a grant of land 'Given at Llanidan. Llanidan became a vicarage under the monastery, endowed with the third part of the emolument for the performance of the rites of religion. Evidence suggests that it became an Augustinian grange with a residence for the Prior, and cellars beneath the house probably date from this time.
In 1535 Beddgelert and its lands was granted in exchange to the monastery of Chertsey in Surrey. In 1537 it passed to the Abbey of Bisham in Berkshire, then becoming Crown Land, sold by Queen Elizabeth c1582 to Edmund Downham and Peter Ashton, who in turn sold the land in 1605 to Richard ap Rydderch of Myfyrion.
Richard ap Rhydderch, or Justice Prytherch, was MP for Beaumaris and Sheriff of Anglesey and is thought to have built a residence 'on a site which local people called the "cellar" from its being a place where ale was sold' (Evans), probably a reference to the cellars of the monastic grange. The central portion of the present house is thought to be the extent of the house built at this time. The datestone, now set in the NW wall, of 1631 probably refers to the date of completion. He also 'laid out a park in the direction of the sea, surrounded with walls of wrought stone'. When he died in 1652 the house was left to his son, Godfrey, whose daughter, Martha, married Pierce Lloyd (V) of Lligwy. They occupied the house in the latter half of the C17, as did their son, also Pierce (VI), and his wife Mary. Pierce Lloyd VI was described by Rowlands as '...continually enlarging and ornamenting his residence at a very considerable expense...', and some of the interior detail, such as the bolection moulded panelling may date from this time. The house was then inherited by his son, Thomas, who moved to Shrophire after his marriage in 1728, leaving the house occupied by his agent Francis Dorsett. Thomas had no legitimate heirs and when he died in 1740 the house was sold to meet his debts.
Llanidan Hall, the estate and the rectorial rights were bought by Henry Paget, 7th Baron Paget and 1st Earl of Uxbridge, who left them to his nephew, Sir William Irby, afterwards the first Lord Boston. The house became the Anglesey residence of his descendants until George Ives, Lord Boston moved to Porthamel and the house was tenanted by agents of the estate. By 1772 the house was leased to Thomas Williams who, in 1785, also became chief agent to the Parys Copper Mine, the position which earned him his fortune and also the nickname of 'Twm Chwareu Teg (Tom fair play). Williams spent some of his fortune improving the house at Llanidan, much of the external character of the house dating from the rebuilding and remodelling work carried out at this time. Late C18 work includes an addition to the SE side of the house incorporating a projecting canted bay, probably built of brick. Part of this addition was built over the old cellars and part of the older house may have had to be demolished for it to be built; the ground floor rooms contain panelling that may have come from the older house. Some rooms also contain copper glazing bars, favoured by John Cooper, thought to have been the architect employed for this work. A long service wing also added to the NE may be earlier C18. Thomas Williams also remodelled the grounds, building the Ha-Ha which runs round the SE side of the garden, as well as the Lodge and main drive to the house.
In the C19 the house was tenanted and, for a while, was home to Lord Boston. A wing on the SW side of the house, was demolished shortly after the First World War, though surviving cellars beneath it are now used as a water reservoir. In 1937 another cellar, under the terrace E of the house, was excavated to form a dining room for the tenant of the time, Alfred Clegg. In the latter half of C20 the house fell into a state of disrepair, but has been extensively restored in recent years by the current owners.