He was the son of William Rainsborough, a captain and Vice-Admiral in the Royal Navy, and ambassador to Morocco. Before the war, Thomas and his brother, William Rainsborowe, were both involved in an expedition to the PuritanProvidence Island colony, off the coast of Nicaragua and the Rainsborough family had previous marriage links to Massachusetts. Thomas Rainsborough was devout in his religious beliefs and was a Fifth Monarchist.
Military career
Rainsborough served in the Parliamentary forces during both the first and second English Civil Wars. Originally a naval officer he commanded the Swallow, the Lion and other English naval vessels during the first civil war. By May 1645, he was a Colonel in the New Model Army having raised an infantry regiment. Rainsborough took an active part in the battles at Naseby and Bristol. In 1645 he captured the symbolic stronghold of Berkeley Castle for Parliament before moving to the siege of Oxford, which surrendered the following June. Later in 1646, he helped conclude the Siege of Worcester and was made the city's governor. In 1648 Rainsborough was moved from the army and given, by Parliament, command of the navy, holding the rank of Vice-Admiral. His appointment was unpopular with both officers and sailors, resulting in a mutiny of six ships on 27 May 1648. In the same year he briefly replaced the Royalist sympathiser William Batten as Captain of Deal Castle, but was dismissed when the castle also declared for the King. Despite his previous experience, Rainsborough was viewed by the navy as being too radical and having been imposed on them by the army. As a result of the mutiny the Earl of Warwick was appointed Lord High Admiral, with Rainsborough returning to the army. On his return to the army, Rainsborough led the siege and victory at Colchester. From Colchester he was tasked with taking Pontefract Castle and it was during this siege he was killed.
Rainsborough was the most senior member of the Army Council to support the Leveller proposals. During the Putney Debates his arguments for universal suffrage were called 'anarchy' by Henry Ireton, who spoke for the Army Grandees. During the debates, Rainsborough said:
Death and controversy
In October 1648, Rainsborough was sent by his commander, Sir Thomas Fairfax, to the siege at Pontefract Castle. Whilst he was in nearby Doncaster, he was killed by four Royalists during a bungled kidnap attempt. The site is still marked today by a plaque outside of the House of Fraser. As Rainsborough was under Cromwell's disfavour and there were tensions between Rainsborough and the commander he was displacing, Henry Cholmeley, who later defected to the Royalists, many at the time wondered whether there was some Parliamentary complicity in his death, as do historians today. However Royalist Propaganda may also have played a part in all the rumours. The four Royalists involved in the bungled kidnap crossed the River Don at Mexborough and hid out at Conisborough Castle before their failed attempt. His murder was the subject of a ballad, published in 1648 called "Colonell Rainsborowes ghost or, a true relation of the manner of his death, who was murthered in his bed-chamber at Doncaster, by three of Pontefract souldiers who pretended that they had letters from Lieutenant General Cromwell, to deliver unto him."
Funeral 1648
His funeral was the occasion for a large Leveller-led demonstration in London, with thousands of mourners wearing the Levellers' ribbons of sea-green and bunches of rosemary for remembrance in their hats. He was buried in St John's Churchyard, Wapping. After his death, his brother, William Rainsborowe, continued in the Ranter cause.
