The ancient family of Perrot are said to have derived their surname from Castle Perrott in Britanny, built in 957AD by William de Perrott. His great-grandson, Sir Richard, Seigneur de Perrott in 1066, furnished William The Conqueror with his quota of ships and men and accompanied the expedition to England and initially settled in Somerset, where the river Perrott rises before it runs into the Severn. Sir Richard left issue by his wife, daughter of King Sancho of Aragon, a son and heir, Stephen, who was granted lands by King Henry I of England in Pembrokeshire. He is said to have married Helen (or Eleanor), lady of Yestington, fourth in descent from Howel Dda, king of South Wales. Stephen Perrott erected Narbeth Castle in or about 1112. He left numerous issue.
A descendant, Sir John Perrot, KB, Lord of Haroldston and of Langhorn, which castle he built, was also Lord of Carew and its castle, in Pembrokeshire, to which he added substantially. He was Lord Deputy of the Province, Lieutenant-General and sometime Governor of Ireland under Elizabeth I, Admiral of England, Privy Councillor, and possessed estates said to be worth an annual revenue of £22,000 per annum. He married twice. By his first wife he had a son, Sir Thomas Perrott, 1st Baronet of Haroldston, created June 28, 1611, who died before his Letters Patent was even issued, having married in 1583 Lady Dorothy, sister of Robert Devereux, 2nd Earl of Essex. (Sir Thomas's issue is unclear but he had at least two daughters: Dorothy, who married a cousin, James Perrott, Lord of Wellington, and Elizabeth, who married John Pryse of Gogerthan.) Sir John's eldest son by his second wife was Sir James Perrott, Knt., Privy Councillor, who was created Marquess of Narbeth, Earl and Viscount Carew, and Baron Perrott. This family suffered greatly for being cavaliers during the civil war, their estates ravaged.