Henry Jermyn, 1st Earl of Saint Albans KG (25 March 1605 (baptised) – January 1684) was an English Royalist politician, diplomat, courtier and property developer.

Having formed an intimate friendship with Henrietta Maria of France in the 1630s, he constantly devised and promoted schemes to involve foreign powers in the restoration of the monarchy, both before and after the execution of Charles I in 1649.

[1] In 1625, while still underage, Jermyn was elected Member of Parliament for Bodmin on the interest of his uncle Sir Robert Killigrew, and was re-elected MP for the seat in 1626.

In around 1627, he came to the attention of Henrietta Maria, Queen consort of Charles I of England, and was appointed a gentleman usher in her private household.

[2] The brothers were both elected MPs for Bury St Edmunds in the Long Parliament in November 1640 and were active and ardent Royalists.

On 8 September 1643 he was raised to the peerage as Baron Jermyn of St Edmundsbury,[4] ostensibly so that, should he fall into Parliamentarian hands, he would be beheaded, and not hanged, drawn and quartered.

A few months later he accompanied Henrietta Maria to France, where he continued to act as her secretary and confidant, and attempted to raise support for the Royalist war effort.

[1] In France, Jermyn became the leading figure in the 'Louvre faction', a group of English royalists who had attached themselves to Henrietta Maria's court-in-exile, based initially out of the Louvre Palace.

The group was marked by their close adherence to Henrietta Maria, their pro-French outlook and their opposition to the influence of Hyde over Charles II.

[9] When Charles went to Breda, Jermyn remained in Paris with Henrietta Maria, who persuaded her son to create him Earl of St Albans on 27 April 1660.

[12] St Albans' obvious affinity with France was controversial at court; the Italian diplomat Lorenzo Magalotti wrote that he was "a man who is wholly devoted to French interests and who acts with no other purpose than to promote the vast projects of that crown at whatever cost to England".

He briefly served in the First Danby ministry as Lord Chamberlain, but left office in 1674 after which he largely retired from public life.

The City of London, which feared for its water supply, was hostile to the plan, but the support of Charles II for the development discouraged opposition.

The grant by Charles of the freehold of the new square and other adjacent property to trustees for the Earl of St Albans was made on 1 April 1665.

[4] Gossip which the historian Henry Hallam accepted as authentic, but which is supported by no real evidence, asserted that Jermyn was secretly married to Queen Henrietta Maria during their exile in France.