William Mansfield, 1st Baron Sandhurst

General William Rose Mansfield, 1st Baron Sandhurst GCB GCSI PC (21 June 1819 – 23 June 1876) was a British military commander who served as Commander-in-Chief of India from 1865 to 1870.

Portrait from the Illustrated London News 13 May 1865

Mansfield was born in Ruxley, Kent, the fifth of the seven sons of John Mansfield of Diggeswell House in Hertfordshire, and his wife, daughter of General Samuel Smith of Baltimore in the United States. His grandfather was the prominent lawyer Sir James Mansfield, Solicitor General from 1780 to 1782 and in 1783 and Chief Justice of the Common Pleas from 1804 to 1814.

In 1854, he married Margaret Fellowes, who became a noted suffragist and spiritualist after his death.

Mansfield was educated at Royal Military College, Sandhurst, and was commissioned into the 53rd Foot as an ensign in 1835. He was promoted to lieutenant on 31 August 1838 and to captain on 10 February 1843. He was mostly active in India and served in the Sutlej campaign of 1845 to 1846. Promoted to major on 3 December 1847, he commanded the 53rd Regiment in the Punjab from 1848 to 1849 and was employed in the Peshawar operations in 1851 and 1852, receiving promotion to lieutenant-colonel on 9 May 1851 and to colonel on 6 October 1854.

In 1855, during the Crimean War, Mansfield was appointed military adviser to the Ambassador at Constantinople Lord Stratford de Redcliff, and accompanied him to the Crimea. He then returned to India and served as Chief-of-Staff during the Indian Mutiny campaign from 1857 to 1859, initially with the local rank of major-general. His role during the Siege of Lucknow in November 1857 saw his appointment as Knight Commander of the Order of Bath (KCB) in March 1858. Promoted to major-general on 18 May 1858, he served as Commander-in-Chief of the Bombay Army from 1860 to 1865 and as Commander-in-Chief, India from 1865 to 1870. During this time, he was made Knight Grand Commander of the Order of the Star of India (GCSI) and subsequently Knight Grand Cross of the Order of the Bath (GCB). Mansfield was then Commander-in-Chief, Ireland from 1870 to 1875. He was promoted to full general on 23 May 1872.

In 1871 he was admitted to the Irish Privy Council and raised to the peerage as Baron Sandhurst, of Sandhurst in the County of Berkshire.

Sandhurst died in London on 23 June 1876, aged 57, and was buried at Digswell church, Hertfordshire. He was succeeded in the Barony by his eldest son William, who was created Viscount Sandhurst in 1917. However, this title became extinct on his death while he was succeeded in the Barony by his younger brother.