THE WESTENRAS, descended from the family of VAN WASSENAER, of Wassenburg, were of great antiquity in Holland, and they bore the augmentation of the SEAHORSE, in reference to the valour of an ancestor who, during the Duke of Alba's campaigns, was actively employed against the enemy, and undertook to swim across an arm of the sea with important intelligence to his besieged countrymen.
WARNER WESTENRA settled in Ireland during the reign of CHARLES II, and with his brothers, Derrick and Peter Westenra, became a free denizen of that kingdom, by act of parliament, in 1662.
In 1667, Colonel Grace sold the town and lands of "Clonlee, Brickanagh, and Lyagh" [sic], in the King's County, to this Warner Westenra, merchant, of the city of Dublin.
He married Elizabeth Wyhrantz, and had issue,
HENRY, his successor;Mr Westenra died in 1676, and was succeeded by his son,
Elizabeth, m Rt Rev Simon Digby.
HENRY WESTENRA, who inherited likewise the estates of his cousin, Peter Westenra, MP for Athboy.
Mr Westenra wedded, in 1700, Eleanor, second daughter of Sir Joshua Allen, Knight, and sister of John, 1st Viscount Allen, by whom he had surviving issue,
WARNER, his successor;Mr Westenra died in 1719 and was succeeded by his eldest son,
Elizabeth; Jane; Penelope.
WARNER WESTENRA, MP for Maryborough in 1728, who espoused, in 1738, Lady Hester Lambert, second saughter of Richard, 4th Earl of Cavan, and had issue,
HENRY, his successor;Mr Westenra was was succeeded by his eldest son,
HENRY WESTENRA, MP for Monaghan, and seneschal of the King's manors in Ireland, who married, in 1764, Harriet, daughter of Colonel John Murray, MP for County Monaghan, and had issue,
WARNER WILLIAM, his heir;He was succeeded by his eldest son,
Mary Frances; Harriet Hesther.
WARNER WILLIAM WESTENRA (1765-1842), of Rossmore Park, County Monaghan, who wedded firstly, in 1791, Mary Anne, second daughter of Charles Walsh, of Walsh Park, County Tipperary, by whom he had issue,
HENRY ROBERT, his successor;His lordship espoused secondly, in 1819, Augusta, fourth daughter of of Francis, Lord Elcho, and sister of Francis, 7th Earl of Wemyss.
He succeeded to the barony of ROSSMORE at the decease of ROBERT CUNINGHAME, 1st Baron Rossmore, in 1801
GENERAL ROBERT CUNINGHAME fought in the Battle of Culloden in 1746, with the 14th Foot.
He was aide-de-camp to the Lord Archbishop of Armagh in 1751, when the latter was Lord Justice of Ireland.
General Cuninghame was elevated to the peerage, in 1796, by the title of BARON ROSSMORE, of Rossmore Park; and having no issue by his wife, Elizabeth, daughter of John Murray, and co-heir of her mother Mary, Dowager Lady Blayney, sole heir of Sir Alexander Cairnes Bt, the patent of creation contained a reversionary clause conferring the Barony, at his lordship's decease, upon the heirs male, at the time being, of two of her ladyship's sisters successively; namely, Anne, the wife of the Rt Hon Theophilus Jones; and Harriet, the wife of Henry Westenra.
His lordship died in 1801, and the only son of Mrs Jones, Alexander Jones, having predeceased him, unmarried, the barony devolved upon Mrs Westenra's eldest son, WARNER WILLIAM WESTENRA, 2nd Baron Rossmore.
The heir apparent is the present holder's only son, the Hon Benedict William Westenra (b 1983).
- Robert Cuninghame, 1st Baron Rossmore (d 1801);
- Warner William Westenra, 2nd Baron (1765–1842);
- Henry Robert Westenra, 3rd Baron (1792–1860);
- Henry Cairnes Westenra, 4th Baron (1851–74);
- Derrick Warner William Westenra, 5th Baron (1853–1921);
- William Westenra, 6th Baron (1892–1958);
- William Warner Westenra, 7th Baron (b 1931).
An extension was added in 1858 in Scottish-Baronial style, designed by William Henry Lynn.
A main feature of the original building was a large square tower and turret with crow-step battlements.
The extension also featured two towers, one with a polygonal turret and cupola, the other a smaller square tower with a spire.
The building underwent further smaller changes, a number of which were inspired by a competition which had developed over the years between Lord Rossmore and Mr Shirley of Lough Fea, as to which of them could claim to have the largest room in County Monaghan.
The remarkable consequence was that the drawing-room in Rossmore Castle was enlarged five times.
Eventually the combined changes and additions resulted in a building with three towers and over 117 windows in 53 different shapes and sizes.
After the 2nd World War, the house developed a severe case of dry rot, and the 6th Baron and his family were forced to leave the castle and take up residence in Camla Vale, a Georgian house owned by the family and situated within the estate grounds.
The castle was demolished in 1974.
The former demesne is now a forest park.
First published in January, 2012.