Life

He was the eldest son of Henry Mordaunt, 4th Baron Mordaunt, a Roman Catholic kept for a year in the Tower of London

Tower of London

Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London, is a historic castle on the north bank of the River Thames in central London, England. It lies within the London Borough of Tower Hamlets, separated from the eastern edge of the City of London by the open space...

 on suspicion of complicity in the Gunpowder Plot

Gunpowder Plot

The Gunpowder Plot of 1605, in earlier centuries often called the Gunpowder Treason Plot or the Jesuit Treason, was a failed assassination attempt against King James I of England and VI of Scotland by a group of provincial English Catholics led by Robert Catesby.The plan was to blow up the House of...

, who died in 1608. The widow, Lady Margaret, daughter of Henry Compton, 1st Baron Compton

Henry Compton, 1st Baron Compton

Henry Compton, 1st Baron Compton was an English peer.Compton was the son of Peter Compton and his wife Anne, daughter of George Talbot, 4th Earl of Shrewsbury, and a relative of Sir William Compton. In 1572 he was summoned to the House of Lords as Baron Compton, of Compton in the County of Warwick...

, also a Catholic, was deprived by James I

James I of England

James VI and I was King of Scots as James VI from 24 July 1567 and King of England and Ireland as James I from the union of the English and Scottish crowns on 24 March 1603...

 of the custody of her child John. He was made a ward of Archbishop George Abbot, and educated at Oxford.

Taken to court by the king, who was struck by his beauty and intelligence, John was made a K.B.

Order of the Bath

The Most Honourable Order of the Bath is a British order of chivalry founded by George I on 18 May 1725. The name derives from the elaborate mediæval ceremony for creating a knight, which involved bathing as one of its elements. The knights so created were known as Knights of the Bath...

 on the occasion of Prince Charles

Charles I of England

Charles I was King of England, King of Scotland, and King of Ireland from 27 March 1625 until his execution in 1649. Charles engaged in a struggle for power with the Parliament of England, attempting to obtain royal revenue whilst Parliament sought to curb his Royal prerogative which Charles...

 being created Prince of Wales

Prince of Wales

Prince of Wales is a title traditionally granted to the heir apparent to the reigning monarch of the United Kingdom of Great Britain and Northern Ireland and the 15 other independent Commonwealth realms...

, 3 November 1616, and was remitted an unpaid fine of £10,000 which had been imposed on his father. By Charles I he was created Earl of Peterborough

Earl of Peterborough

Earl of Peterborough was a title in the Peerage of England. It was created in 1628 for John Mordaunt, 5th Baron Mordaunt . He was succeeded by his eldest son, Henry, the second Earl. He was a soldier and courtier. Lord Peterborough had two daughters but no sons...

, by letters patent

Letters patent

Letters patent are a type of legal instrument in the form of a published written order issued by a monarch or president, generally granting an office, right, monopoly, title, or status to a person or corporation...

 of 9 March 1628.

On the outbreak of the First English Civil War

First English Civil War

The First English Civil War began the series of three wars known as the English Civil War . "The English Civil War" was a series of armed conflicts and political machinations that took place between Parliamentarians and Royalists from 1642 until 1651, and includes the Second English Civil War and...

 he adhered to the parliament, and held the commission of general of the ordnance under the Earl of Essex

Earl of Essex

Earl of Essex is a title that has been held by several families and individuals. The earldom was first created in the 12th century for Geoffrey II de Mandeville . Upon the death of the third earl in 1189, the title became dormant or extinct...

, but he died of consumption

Tuberculosis

Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...

, 18 June 1642. By his wife Elizabeth, daughter of William Howard, 3rd Baron Howard of Effingham

William Howard, 3rd Baron Howard of Effingham

William Howard, 3rd Baron Howard of Effingham was an English nobleman, the eldest son of Charles Howard, 1st Earl of Nottingham and Katherine Carey, Lady of the chamber to Queen Elizabeth who died 25 Feb 1603 at Arundel House, Strand, Middlesex, ENG.As Sir...

, he left two sons: Henry Mordaunt, 2nd Earl of Peterborough

Henry Mordaunt, 2nd Earl of Peterborough

Henry Mordaunt, 2nd Earl of Peterborough, KG, PC, FRS was an English soldier, peer and courtier.-Early life:Styled Lord Mordaunt from 1628, he was the eldest son of John Mordaunt, 1st Earl of Peterborough...

 and John

John Mordaunt, 1st Viscount Mordaunt

John Mordaunt, 1st Viscount Mordaunt was an English royalist.He was born in Lowick, the second son of John Mordaunt, 1st Earl of Peterborough and Elizabeth Howard John Mordaunt, 1st Viscount Mordaunt (18 June 1626 – 5 June 1675) was an English royalist.He was born in Lowick, the second son of John...

, afterwards Lord Mordaunt of Reigate and Viscount Mordaunt of Avalon; and a daughter, Elizabeth, who married Thomas, son and heir to Edward Howard, 1st Lord Howard of Escrick.