John Mordaunt was the first Earl of Peterborough. His beginnings were not auspicious as his father was incarcerated in the Tower of London on suspicion of complicity in the Gunpowder Plot. He died in 1608 when John was 11. John was taken from his Catholic family and was made a ward of Protestant Bishop of London, George Abbot. Abbot believed the best way of dissuading him from following the same path as his father was by a good education; he was therefore educated at Oxford.
After completing his education Mordaunt was invited to court, where he was a great success. Charles I created him Earl of Peterborough, by letters patent of 9 March 1628.
During the English Civil War he deserted the king and fought on the side of Parliament. When he died on 8 June 1642 his son Henry, 2nd Earl of Peterborough defected back to the Royalists.
John Mordaunt had the drama 'Tis Pity She's a Whore' dedicated to him by the playright John Foot.
The earldom died out when the 5th Earl, Charles Henry Mordaunt died, childless, on 16th June 1814.