Napier, Sir William Francis Patrick (1785–1860), general and historian, was born 17 December 1785 at Castletown, near Celbridge, Co. Kildare, third son of Col. the Hon. George Napier and his second wife, Lady Sarah Lennox, seventh daughter of the duke of Richmond and previously wife of Sir Charles Thomas Bunbury, MP. His elder brothers were Gen. Sir Charles James Napier (1782–1853), the conqueror of Scinde, and Gen. Sir George Napier (1784–1855), governor of the Cape of Good Hope. He was a first cousin of Charles James Fox and also of Lord Edward FitzGerald (qv). Educated locally, he entered the British army as an ensign in the Royal Irish Regiment of Artillery on 14 June 1800. Transferring to the 62nd Foot, he was promoted to lieutenant (18 April 1801) but was placed on half pay at the treaty of Amiens in March 1802. He was promoted captain in June 1804, transferring to the 43rd Foot in August, and in 1806 was sent to Ireland on a recruiting tour, with instructions to recruit men from the militia to serve in the line regiments. In July 1807 he served with his regiment under the command of Gen. Sir Arthur Wellesley (qv) during the successful siege of Copenhagen and was present at the battle of Kioge.
In September 1808 he sailed with his regiment to Spain, where he served throughout the Peninsular campaign of Gen. Sir John Moore (qv). He was present at many of the major actions of the later campaigns, including the action at Coa (July 1810), where he was wounded, the battle of Busaco (27 September 1810), and the actions at Pombal and Redinha. At the action at Casal Novo (14 March 1811), he was severely wounded while leading forward six companies of the 52nd Foot in an effort to harass the rearguard of Masséna's army. He later returned to the army, with his wound still open and a bullet lodged near his spine, and was appointed as brigade major to the Portuguese brigade. He took part in the battle of Fuentes d'Onoro (3–5 May 1811) and was promoted to major at the end of the month (30 May 1811). Succumbing to fever, he returned to England; after a period of leave, during which he got married, he returned to Portugal and took command of the 43rd Foot as senior major present. He subsequently served in the battles of Salamanca (22 July 1812), Nivelle (10 November 1813), and Nive (10–13 December 1813), which was Marshal Soult's last attempt to drive the allied army from France. Promoted to lieutenant-colonel in November 1813, he was present at the battle of Orthez (27 February 1814) but had to return to England due to wounds and illness. He was subsequently awarded the gold and silver Peninsular medal, with two and three clasps respectively. Arriving too late in France in 1815, he took no part in the ‘Hundred days’ campaign and retired from the active list in 1819. He was made a CB in the same year.
He devoted the rest of his life to historical writing, initially contributing an article to the Edinburgh Review in 1821. In 1823, at the suggestion of Lord Langdale, he began writing his History of the war in the Peninsula and the south of France, 1807–1814 (6 vols, 1828–40). This epic work, which ran to several editions, made use of material supplied by both the duke of Wellington and the French marshals Soult and Suchet, while papers of Joseph Bonaparte, captured after the battle of Vittoria, were also made available to him. In July 1830 he was promoted to full colonel; promoted to major-general in November 1841, he was appointed lieutenant-governor of Guernsey (1842–7). Appointed colonel of the 27th Foot (the Inniskilling Fusiliers) in February 1848, he was made a KCB (May 1848).
He later published several works centred on his brother, Gen. Sir Charles James Napier (1782–1853), after the latter resigned as commander-in-chief in India. These included History of Sir Charles James Napier's administration of Scinde (1851) and Life and opinions of General Sir Charles James Napier (4 vols, 1857). As both of these works sought to vindicate his brother, they were generally seen to be biased in the extreme. Subsequently promoted to lieutenant-general (11 November 1851) and general (17 October 1859), he spent his later years troubled by ill health. He died 12 February 1860 at his London residence, Scinde House in Clapham Park, and was buried at Norwood cemetery.
He married (February 1812) Caroline Amelia, daughter of Gen. the Hon. Henry Fox and niece of Charles James Fox. They had a large family and, devoted to his children, he was devastated at the deaths of his daughters Henrietta (1826) and Fanny (1833). There is a fine marble statue of him in St Paul's cathedral, London; Napier letters are in the Bodleian Library, Oxford, and the BL.