Henry Sydney (or Sidney), 1st Earl of Romney (8 April 1641 - 8 April 1704) was born in Paris, a son of Robert Sidney, 2nd Earl of Leicester , of Penshurst Place in Kent, England, by Lady Dorothy Percy, a daughter of Henry Percy, 9th Earl of Northumberland, a descendant of Edward III.

Henry was a brother of Philip Sidney, 3rd Earl of Leicester , who was born in 1619; Algernon Sidney, the Republican martyr, who was born at Penshurst Place in 1622 but was executed, having been found party to the "Rye House Plot" 1683; and Robert Sidney.

Henry entered Parliament in 1679 and, as a statesman, was one of the Immortal Seven (the author of the letter, in fact) to invite the Protestant William III of Orange to take the throne through the Glorious Revolution, when King James II was deposed under legislation passed to exclude Charles II's Catholic brother (the Duke of York) from the succession.

He was present at the Battle of the Boyne in 1690, and was later to become employed by King Charles as envoy to The Hague and also served as Lord Lieutenant of Ireland for the period between 1692 and 1693, but began to lose favour at the court under Queen Anne.

Henry Sidney served as Master-General of the Ordnance from 1693 to 1702. Additionally, he was a Lieutenant-General of the Regiment of the First Foot Guards, (Grenadier Guards). He employed the Sidney family emblem on prison uniforms, and other government property.

He died unmarried, on the 8th of April, in 1704, at London 'a proud but drunken man' aged 63.

Further reading

The University of Nottingham Library is in possession of the catalogue of the papers of Hans William Bentinck, 1st Earl of Portland which outline much of Sidneys correspondence.

There further have survived 98 letters between Sidney and George Legge, 1st baron Dartmouth, which include papers written by Dartmouth during his confinement at the Tower.

|- style="text-align: center;" | width="30%" |Preceded by:
Lords Justices | width="40%" style="text-align: center;" |Lord Lieutenant of Ireland
1692–1693 | width="30%" |Succeeded by:
Lords Justices

|- style="text-align: center;" | width="30%" |Preceded by:
The Earl of Portland | width="40%" style="text-align: center;" |Groom of the Stole
1699–1704 | width="30%" |Succeeded by:
The Duchess of Marlborough

|- style="text-align: center;" | width="30%" |Preceded by:
Vacant | width="40%" style="text-align: center;" |Master-General of the Ordnance
1693–1702 | width="30%" |Succeeded by:
The Duke of Marlborough