Osborne family, Dukes of Leeds

Sir Edward Osborne (d. 1592), Lord Mayor of London, acquired the Kiveton Park estate at Harthill (Yorkshire, West Riding) by marriage to the daughter and heir of Sir William Hewitt. He also owned Parsloes (Essex). His grandson Sir Edward Osborne (created a baronet in 1620) bought further Yorkshire property but sold Parsloes in 1619. Sir Thomas Osborne, 2nd Bt (d. 1712), the statesman, was created Earl of Danby in 1674, Marquess of Carmarthen in 1689 and Duke of Leeds in 1694. His additions to the family estates included the manor of Wakefield (Yorkshire, West Riding). The lordship of Conisborough (Yorkshire, West Riding), formerly owned by the Coke family of Longford (Derbyshire), was acquired in the mid-18th century. The 2nd Duke (d. 1729) married in 1682 Bridget, daughter and heir of Sir Thomas Hyde, 2nd Bt, of Aldbury (Hertfordshire). The marriage brought Hertfordshire estates (Aldbury, sold 1736 to the first Duke of Bridgewater; Tring, sold 1758; and North Mimms, sold 1799), with Wingrave (Buckinghamshire, sold 1776) and property in Dorset (sold before 1692).

The Hornby Castle (Yorkshire, North Riding) estate entered the family in 1784 on the death of Amelia, suo jure Baroness Darcy and Baroness Conyers. She was the wife of Francis Osborne (d. 1799), Marquess of Carmarthen (later 5th Duke of Leeds) and daughter and heir of the 4th Earl of Holdernesse (d. 1778). The Hornby Castle estate had descended in the Darcy family, Barons Darcy and Barons Conyers (created Earls of Holdernesse in 1682), since its acquisition through the marriage of Thomas Darcy (d. 1605) and Elizabeth, daughter and co-heir of John, Baron Conyers (d. 1557). From 1811, when Kiveton was demolished, it was the main seat of the Dukes of Leeds, although Mar Lodge (Aberdeenshire) was also acquired as a family residence in the 19th century.

In 1785, on the death of the 2nd Baron Godolphin of Helston, cousin and heir of the 2nd Earl of Godolphin (d. 1766), the entailed Godolphin family estates descended to the Marquess of Carmarthen through his mother Mary, daughter of the 2nd Earl and his wife Henrietta, suo jure Duchess of Marlborough. These consisted principally of Cornish estates near Helston, where the Godolphin family had been established since the middle ages, and the Scilly Isles (on lease from the Crown since the reign of Elizabeth I), with property in St James's Place (Middlesex), a Cambridgeshire estate (Gog Magog Hills in Stapleford, apparently bought by the 2nd Earl of Godolphin from Sir William Halton in 1734) and property in Suffolk (Newmarket, purchased by the 2nd Earl, 1730-44). Also inherited was the Baylies estate in Stoke Poges (Buckinghamshire) bought in 1718 by Henry Godolphin (d. 1738, brother of the 1st Earl, and father of the 2nd Baron), together with Farnham Royal, bought by the 2nd Baron from the Earl of Leicester in 1752 (see Coke, Earls of Leicester). The Buckinghamshire and Cambridgeshire estates were later settled on Francis Godolphin Osborne, second son of the 5th Duke of Leeds, created Baron Godolphin of Farnham Royal 1832, whose son the 2nd Baron succeeded his cousin as 8th Duke in 1859. (The Cambridgeshire estate was sold in 1885.) The Godolphin estate of Abertanat (Shropshire), with property in Denbighshire (Tanyllwyn) and Montgomeryshire (Broniarth), did not descend to the Marquess of Carmarthen but to Margaret Ormsby, the 2nd Baron Godolphin’s niece, and thence to the Ormsby Gore family, Barons Harlech.

The 6th Duke (d. 1838) bequeathed unentailed property in Yorkshire (North and West Ridings), including the manors of Wakefield and Conisborough and lands in Wales (Yorkshire, West Riding), with a mansion in St James's Square, to his son-in-law Sackville Lane-Fox (d. 1874), third son of James Lane-Fox of Bramham (Yorkshire, West Riding). In 1859, on the 7th Duke's death, Lane-Fox also succeeded to the baronies of Conyers and Darcy. This inheritance passed to his son Sackville George Lane-Fox (d. 1888), whose elder daughter, Marcia Lane-Fox (afterwards Baroness Fauconberge and Conyers), married the 4th Earl of Yarborough in 1886, subsequently bringing former Osborne property to that family (see Anderson-Pelham, Earls of Yarborough).

Extensive papers of the Dukes of Leeds were sold in 1868-9 and the remainder were dispersed on the sale of Hornby Castle in 1930. Certain Godolphin family papers passed to the Wentworth-Fitzwilliam family through the marriage of the 2nd Baron Godolphin of Helston to his second wife Anne (d. 1805), daughter of the 2nd Earl Fitzwilliam (see Wentworth-Fitzwilliam of Milton).

Estates in 1883: Yorks NR and WR 14,772 acres, Cornwall 5,911 acres, Bucks 3,117 acres, Cambs 436 acres, Middlesex 1 acre, total 24,237 acres worth £33,881 a year.