Fonds GB 0210 PLYMOUTH - Plymouth Estate Records,

Elizabeth Lewis (d. 1733) of Van, St Fagans, and Soberton, Hampshire, the sole heiress of Thomas Lewis of Van, married Other Windsor (1707-32), 3rd earl of Plymouth (second creation). At the time of Thomas Lewis's death in 1736, the estate was so encumbered with debts that the interest exceeded the rental, and three private Acts of Parliament were obtained to sell the estate. The estate was in fact purchased by the trustees of Elizabeth Lewis's marriage settlement for £47,000. St Fagans castle became the Glamorgan seat of the Windsor family.

Other and Elizabeth's only son and heir, Other Lewis Windsor, 4th earl (1731-71) was succeeded by his son Other Hickman, 5th earl (1751-1799), who was succeeded by his only son and heir, Other Archer Windsor, 6th earl (1789-1833, dsp.), on whose death the barony of Windsor de Stanwell fell into abeyance. The Rev. Andrews Windsor (1754-1837, dsp.) succeeded as 7th earl, being a younger brother of the 4th earl, and he was succeeded by his brother Henry Windsor, 8th earl (1768-1843, dsp.)on whose death the earldom became extinct.

In 1855 the abeyance of the barony of Windsor was terminated in favour of Harriet Clive (1797-1869), one of the sisters of the 6th earl, who had married in 1819 with Robert Henry Clive, MP, 2nd son of the 1st earl of Powys. She assumed the additional surname Windsor in 1855. Her son and heir apparent Robert Windsor-Clive, MP, dying before her, Harriet was succeeded by her grandson Robert George Windsor-Clive (1857-1923), who was created Viscount Windsor of St Fagans and Earl of Plymouth (third creation) in 1905. He was succeeded by Ivor Miles Windsor-Clive, 2nd earl (1889-1943), who was succeeded by his son Other Robert Ivor Windsor-Clive, 3rd earl (b. 1923). The family also acquired the Alrhey estate in Flintshire through marriage with the Ellis family in the 18th century.

According to the 1873 return of owners of land, Lord Windsor owned an estimated 15,383 acres in Wales (all in Glamorgan and Flintshire), with an estimated annual rental of £39,069.