Born in 1652 Henry St John was the second child and eldest son of Sir Walter and Lady Johanna. He grew up at the Battersea Manor House under the stern eye of his Puritan mother during the austere post war years of the Commonwealth.
With the restoration of the monarchy in 1660 it could be fairly said that Henry entered into the spirit of the new age. Anxious to save him from his worst excesses, Sir Walter and Lady Johanna swiftly married him off in 1673 to Mary Rich, the daughter of the Earl of Warwick. Sir Walter settled the Lydiard estate on his eldest son and the newly weds divided their time between Battersea and Wiltshire.
But in 1684 Henry was between marriages. His first wife Mary had died in 1678 following the birth of their only surviving child and his second wife to be, Angelica Pelissary had just arrived in England bethrothed to her first husband Philip Wharton.
Temporarily let off the marital leash, Henry fully indulged his predilection for partying, gambling and racing. It was during a night out with the boys in that popular watering hole, the Devil Tavern, Fleet Street, that the talk turned to who owned the best horses.
Along with Sir William Estcott, MP for Malmesbury, and Henry's cousin Edmund Richmond-Webb, the group left the Devil and moved on to the Globe, round the corner in Shoe Lane. A Tryal of Racing between Henry and Sir William was proposed with a bet of £100 - but then it all got rather out of hand. Some insults were bandied about - Henry called Escott an ass who replied that Henry was a fool.
Out came the weapons and before you could say 'calm down boys' Estcott lay dead on the tavern floor. Henry and Edmund were committed to Newgate prison to await their appearance at the Old Bailey where they were jointly charged with murder and manslaughter.
On December 13 the two men were sentenced to death; their estates seized by the crown. But Henry and Edmund had friends and family in high places. Henry's cousin Barbara, Countess of Castlemaine, long time mistress of the King and mother of five of his illegitimate children, interceded for them.
Henry decided a move abroad might be advisable, but he wasn't gone long. By March 1685 he was back in England where he was returned as MP for the family seat at Wootton Bassett.
Did he see the error of his ways? It's doubtful, but he never killed anyone else - well not as far as we know.
He went on to marry Angelica Pelissary on January 1, 1686/7 although he never did quite fit the bill as family man, and his eldest son, the statesman Henry, Viscount Bolingbroke, loathed him.
Unlike poor Sir William, whose family line was wiped out when he died aged 30, Henry lived another 58 years. He died in 1742 aged 89 and was buried at St Mary's Church, Battersea.
Come and hear more about Barbara, Countess of Castlemaine at my portrait tour The Ladies of Lydiard, part of the Behind Closed Doors series of talks and tours at Lydiard House. For more information visit the Friends of Lydiard Park website. All talks and tours are free but spaces are limited so you need to book by phoning Charlotte Thwaites on 01793 465277 or emailing CThwaites@swindon.gov.uk.