Sidney family, Viscounts de l'Isle

By the 15th century the Sidney family owned estates in Surrey (Alfold near Cranleigh), and in Sussex. These were sold in the early 16th century by Sir William Sidney (d. 1554), who received grants of property in the north and east ridings of Yorkshire. In 1539 he exchanged these for the Robertsbridge Abbey (Sussex) estates, which were retained until their sale to Sir Robert Webster in 1726. The Penshurst (Kent) estate was granted to him by Edward VI in 1552. Sir Henry Sidney (d. 1586), Sir William's son, was co-heir through his grandmother Anne, daughter of Sir William Brandon, to the last Brandon Duke of Suffolk and from him inherited property including the Cromwell family foundation of Tattershall College (Lincolnshire), with former Cromwell family manors in Lincolnshire, Leicestershire, Norfolk, Nottinghamshire and elsewhere. This was largely sold to the Earl of Lincoln in 1574 and descended to the Earls Fortescue.

Sir Henry's son Robert Sidney (d. 1626) was created Baron Sidney 1603, Viscount Lisle 1605 and Earl of Leicester 1618. He inherited Leicester House, Westminster, and property in Warwickshire on the death of his uncle Robert Dudley, Earl of Leicester, in 1588 and was bequeathed by Anne Dudley, Dowager Countess of Warwick (d. 1604), a claim to the Berkeley family estates in Gloucestershire, which gave rise to litigation but no permanent passage of property to the Sidney family. Through his marriage in 1584 to the daughter and heir of John Gamage, Robert Sidney acquired the Coity (Glamorganshire) estate, while in 1604 he was granted the honour of Otford (Kent).

The 4th Earl of Leicester was succeeded on his death in 1702 by three sons in turn as 5th, 6th and 7th Earls. The 5th Earl (d. 1705) and another son, the Hon. Thomas Sidney (d. 1728), married the sisters and co-heirs of Sir Robert Reeve, 2nd Bt, of Thwaite (Suffolk), thereby acquiring property in Norfolk (Ranworth, Panxworth, etc) and Suffolk (Thwaite, Monewdon, etc). On the death of the 7th Earl without legitimate issue in 1743, the family peerages were extinguished but the estates descended to Elizabeth, younger daughter of the Hon. Thomas Sidney and wife of William Perry (d. 1759) of Turville Park (Buckinghamshire). The Glamorganshire estate was settled, however, on an illegitimate daughter of the 7th Earl, who married Henry Streatfeild of Chiddingstone (Kent) in 1752; and some division of the Thwaite property occurred in connection with the claims of Elizabeth Perry's sister Mary (d. 1758, wife of Sir Brownlow Sherrard, 4th Bt). The bulk of the Sidney property, however, and the Perry estates in Buckinghamshire and Oxfordshire (Chalgrove, Pyrton), with property in Gloucestershire, Herefordshire (Eardisley, Knighton) and Radnorshire (Old Radnor), passed to Elizabeth, the daughter of William Perry. She married, as his second wife, Bysshe Shelley of Castle Goring (Sussex). Her estates devolved upon the eldest son of this marriage, Sir John Shelley-Sidney (d. 1849), who took the surname Sidney in 1793 and was created a baronet in 1818. His son was raised to the peerage as Baron De L'Isle and Dudley in 1835. The 6th Baron was created Viscount De L’Isle in 1956. The Dudley inheritance, except for the Leicester House estate in Westminster, appears to have been disposed of in the 17th century and the family property outside Kent (eg Turville, sold 1796) to have been alienated by the early 19th century.

In 1850 the 2nd Baron married the daughter and heiress of Sir William Foulis, 8th Bt, of Ingleby Manor (Yorkshire, North Riding). Ingleby had been purchased in 1608 by Sir David Foulis, created a baronet in 1620, and the North Riding estate was extended by his son Sir Henry Foulis, through his marriage to the daughter of Sir Thomas Layton of Sexhow.

Estates in 1883: Yorks NR 4,896 acres, Kent 4,356 acres, total 9,252 acres worth £10,232 a year.