Warren, Sir Peter (1703–52), admiral in the British navy, was born 10 March 1703 at Warrenstown, Co. Meath, third son among three sons and two daughters of Michael Warren, Roman catholic landowner, and Catherine Warren (née Aylmer). Educated locally, he entered the Royal Navy in 1716, under the supervision of his uncle Adm. Matthew Aylmer (qv), and soon converted to protestantism. Rising rapidly, thanks to his ability as well as to the patronage of his relative, he became a midshipman in 1719 and a lieutenant in 1723. Given command of the Grafton, he was made a captain in 1727, and stationed in the Baltic. In 1730 he was sent to America as captain of the Solebay and he spent much of the next seventeen years based at New York. His nephew was William Johnson (qv), whom he brought to America in 1738, and he appointed him manager of the extensive land holdings he purchased. His home was at Greenwich House, on the Hudson river, and he owned 300 acres of what is now Greenwich Village. Warren quickly amassed a large fortune, thanks in large part to the prize money he won in various naval encounters. With the outbreak of war with Spain, he commanded a squadron in Jamaica (1744), and the following year won many battles against the French. He commanded the British fleet at the siege of Louisbourg, Cape Breton Island (1745), and captured prizes that were estimated to total £1 million; Warren's share was the ‘admiral's eighth’. Refused a baronetcy because he had no heir at that time, he was instead made rear-admiral and appointed governor of Cape Breton. Returning to England (December 1746), he was immediately dispatched to fight the French fleet at Cape Finisterre. He won a brilliant victory (3 May 1747) and became a hero in England; he was made a KB and was given command of the western squadron. Cashing in on his popularity, he ran for parliament and was elected for Westminster in 1747; his expenses, however, came to £7,000. On 12 May 1748 he was promoted to vice-admiral but ill-health prevented him from returning to active service. Believed by contemporaries to be the richest commoner in Britain, he invested his money carefully, engaged in various philantropic ventures, and purchased a large estate, Westbury, in Hampshire. In parliament he unwisely attached his fortunes to the prince of Wales, and when the prince died (1751) Warren was left without a patron.
Warren died 29 July 1752 in Dublin of a violent fever, while on a visit to purchase some estates in Ireland. He was buried near his birthplace at Warrenstown, and a large monument was erected in his honour at Westminster abbey. He married (1731) Susanna de Lancey; they had one son and four daughters.