During the period of increasing tensions leading up to the First Anglo-Dutch War of 1653, Marvell wrote the satirical "Character of Holland," repeating the then current stereotype of the Dutch as "drunken and profane": "This indigested vomit of the Sea,/ Fell to the Dutch by Just Propriety."
He became a tutor to Cromwell’s ward, William Dutton, in 1653, and moved to live with his pupil at the house of John Oxenbridge in Eton. Oxenbridge had made two trips to Bermuda, and it is thought that this inspired Marvell to write his poem Bermudas. He also wrote several poems in praise of Cromwell, who was by this time Lord Protector of England. In 1656 Marvell and Dutton travelled to France, to visit the Protestant Academy of Saumur.
In 1657, Marvell joined Milton, who by that time had lost his sight, in service as Latin secretary to Cromwell's Council of State at a salary of £200 a year, which represented financial security at that time. Oliver Cromwell died in 1658. He was succeeded as Lord Protector by his son Richard. In 1659 Marvell was elected Member of Parliament for Kingston-upon-Hull in the Third Protectorate Parliament. He was paid a rate of 6 shillings, 8 pence per day during sittings of parliament, a financial support derived from the contributions of his constituency. He was re-elected MP for Hull in 1660 for the Convention Parliament.