Question: Robert Collier, 2nd Baron Monkswell was briefly Under-Secretary of State for War under a man who was known by the courtesy title of?

Context paragraphs:
Archibald Primrose, 5th Earl of Rosebery: Archibald Philip Primrose, 5th Earl of Rosebery, 1st Earl of Midlothian, (7 May 1847 – 21 May 1929) was a British Liberal statesman who served as Prime Minister of the United Kingdom from 5 March 1894 to 22 June 1895.  Between the death of his father, in 1851, and the death of his grandfather, the 4th Earl, in 1868, he was known by the courtesy title of Lord Dalmeny.

John Stuart-Wortley, 2nd Baron Wharncliffe: John Stuart-Wortley-Mackenzie, 2nd Baron Wharncliffe FRS (20 April 1801 – 22 October 1855), was a British Tory politician.  He served briefly as Under-Secretary of State for War and the Colonies between December 1834 and January 1835.

Baron Monkswell: Baron Monkswell, of Monkswell in the County of Devon, is a title in the Peerage of the United Kingdom.  It was created in 1885 for the lawyer and Liberal politician Sir Robert Collier.  His eldest son, the second Baron, served as Under-Secretary of State for War in 1895 in the Liberal administration of Lord Rosebery.  His grandson, the fourth Baron (who succeeded his uncle in the title), disclaimed the peerage on 7 April 1964.  He had earlier been a member of the Essex County Council.  s of 2010 the title is held by his eldest son, the fifth Baron, who succeeded in 1984.  He was previously a member of the Manchester City Council for the Labour Party.

Robert Collier, 3rd Baron Monkswell: Robert Alfred Hardcastle Collier, 3rd Baron of Monkswell (13 December 1875 – 14 January 1964), known as Robert Collier before 1909, was a British aristocrat and writer on railways.

Robert Collier, 2nd Baron Monkswell: Robert Collier, 2nd Baron Monkswell (26 March 1845 – 22 December 1909), was a British Liberal politician.  He was briefly Under-Secretary of State for War under The Earl of Rosebery in 1895.  As a young man, he was a first-class cricketer active from 1866 to 1867.  He was born and died in Chelsea.

Earl of Harrowby: Earl of Harrowby, in the County of Lincoln, is a title in the Peerage of the United Kingdom.  It was created in 1809 for the prominent politician and former Foreign Secretary, Dudley Ryder, 2nd Baron Harrowby.  He was made Viscount Sandon, of Sandon in the County of Stafford, at the same time, which title is used as a courtesy title by the heir apparent to the earldom.  His son, the second Earl, held office under Lord Palmerston as Chancellor of the Duchy of Lancaster and Lord Privy Seal.  He was succeeded by his eldest son, the third Earl.  He was a Conservative politician and notably served as President of the Board of Trade from 1878 to 1880.

Earl of Morley: Earl of Morley, of Morley in the County of Devon, is a title in the Peerage of the United Kingdom.  It was created in 1815 for John Parker, 2nd Baron Boringdon.  At the same time he was created Viscount Boringdon, of North Molton in the County of Devon, which is used as a courtesy title by the heir apparent to the earldom.

Earl Beatty: Earl Beatty is a title in the Peerage of the United Kingdom.  It was created in 1919 for the prominent naval commander Admiral of the Fleet David Beatty.  He was created Baron Beatty, of the North Sea and of Brooksby in the County of Leicester, and Viscount Borodale, of Wexford in the County of Wexford, at the same time, also in the Peerage of the United Kingdom.  The latter title is used as a courtesy title for the Earl's eldest son and heir apparent.  Lord Beatty was succeeded by his eldest son, the second Earl.  He represented Peckham in the House of Commons as a Conservative from 1931 to 1936 and briefly served as Under-Secretary of State for Air in Winston Churchill's 1945 caretaker government.  s of 2014 the titles are held by his eldest son, the third Earl, who succeeded in 1972.

Robert Collier, 1st Baron Monkswell: Robert Porrett Collier, 1st Baron Monkswell, PC, QC (21 June 1817 – 27 October 1886) was an English lawyer, politician and judge.

Earl of Cardigan: Earl of Cardigan is a title in the Peerage of England, currently held by the Marquesses of Ailesbury, and used as a courtesy title by the heir apparent to that Marquessate, currently David Brudenell-Bruce, Earl of Cardigan, son of the 8th Marquess.  The Brudenell family descends from Sir Robert Brudenell, Chief Justice of the Common Pleas from 1520 to 1530.  His great-grandson, Sir Thomas Brudenell, was created a Baronet in the Baronetage of England, styled "of Deene in the County of Northampton", on 29 June 1611.  On 26 February 1628, he was raised to the Peerage of England as Baron Brudenell, of Stanton Wyvill in the County of Leicester, and on 20 April 1661 he was further honoured when he was made Earl of Cardigan, also in the Peerage of England.  On his death, the titles passed to his son, Robert, the 2nd Earl, and on the 2nd Earl's death to his grandson, George, the 3rd Earl, the 2nd Earl's only son, Francis, Lord Brudenell, having predeceased his father.

Supporting paragraphs: Robert Collier, 2nd Baron Monkswell Archibald Primrose, 5th Earl of Rosebery
Answer: Lord Dalmeny