Colonel Thomas Horton, January 1603 to October 1649, was a member of the minor gentry from Leicestershire who served in the Parliamentarian army during the Wars of the Three Kingdoms.

His family was closely connected to Sir Arthur Haselrig, one of the Five Members whose attempted arrest by Charles I in January 1642 was a major step on the road to the First English Civil War.

During the 1648 Second English Civil War, Horton played a significant role in ending the revolt in South Wales, and was rewarded with grants of land in Pembrokeshire.

[3] The relationship between Parliament and the Army Council continued to deteriorate, leading to the eviction of the Eleven Members in July, and the occupation of London by the New Model.

[11] What began as a wage dispute led to open revolt in April, when Poyer, Laugharne and Rice Powell declared their support for restoring Charles, beginning the Second English Civil War.

In contrast to Horton's experienced veterans, most of the Royalist troops were untrained and poorly armed; he won an easy victory at St Fagans on 8 May.

[12] Shortly after this victory, Cromwell arrived in Wales with another 6,500 men, and besieged Pembroke Castle; after capturing Tenby, Horton joined him there at the end of May.

[15] In a letter dated 25 October, Cromwell wrote Horton 'is lately dead of the country-disease', usually thought to refer to dysentery, a common disease caused by poor hygiene.

[3] In 1654, Parliament approved a payment to his executors of £1,454 in back pay; as a regicide, his heirs were deprived of their estate at the 1660 Restoration, although this could not have been substantial, while it seems likely his son had already emigrated.