Thomas Rainsborough, or Rainborowe, 6 July 1610 to 29 October 1648, was an English religious and political radical who served in the Parliamentarian navy and New Model Army during the Wars of the Three Kingdoms. One of the few contemporaries whose personal charisma and popularity rivalled that of Oliver Cromwell, he has also been described as "a soldier of impressive professional competence and peerless courage".

The Levellers were a political movement active during the Wars of the Three Kingdoms who were committed to popular sovereignty, extended suffrage, equality before the law and religious tolerance. The hallmark of Leveller thought was its populism, as shown by its emphasis on equal natural rights, and their practice of reaching the public through pamphlets, petitions and vocal appeals to the crowd.