Sir Henry Vaughan of Derwydd, near Llandeilo, Carmarthenshire, was a younger brother of the First Earl of Carbery, John Vaughan of Golden Grove. By the time of the Civil War, the Vaughan's of Golden Grove were the dominant landowner in Carmarthenshire. Henry's nephew, Richard Vaughan had inherited the earldom in 1634, and soon after the outbreak of the Civil war Richard was appointed the Kings Lieutenant General in South Wales.In October and November 1642, the Vaughans seized the Arms of the Trained Bands of the County of Carmarthen, and levied 15 shillings from each of the trained bands members to finance the raising of a regiment of footIt was early 1643 when Vaughan's men arrived at Oxford, and a grateful monarch knighted him on January 1614,

In October and November 1642, the Vaughans seized the Arms of the Trained Bands of the County of Carmarthen, and levied 15 shillings from each of the trained bands members to finance the raising of a regiment of foot

It was early 1643 when Vaughan's men arrived at Oxford, and a grateful monarch knighted him on January 1614,

On 26 October, 1643, Sir Henry was raised to the rank of Sergeant Major General, and sent back to serve in West Wales, suppressing the rebel forces in Pembrokeshire, and raising fresh forces to serve with the Oxford Army. The bulk of the Regiment remained with the Oxford Army under Sir Henry Vaughan's son, (also a Henry Vaughan). Although the Welsh levies at Edgehill were reported to be badly equipped, the troops raised in the next few months not only had access to the substantial Trained bands stores, but also the products of the Iron Foundry on Sir Henry's land at Llandyfan. Also, in March 1643, Vaughans men moved to secure a second Iron works at., Llangyndeirne, which later grew into the steel town of Llanelli

In March 1643/4, Parliament's Navy landed strong forces in Pembrokeshire to support the local rebels, and Sir Henry was forced to vacate Haverfordwest somewhat precipitously, leaving behind a consignment of 'a hundred red coats which were never worn'. This misfortune for the Royalist cause is the reenactor's gain, for thereby we know that Sir Henry's Regiment were dressed in red coats

Sir Henry then fell back on Carmarthen town, which the Vaughans had fortified on the advice of a professional engineer named Captain Richard Steele. A substantial length of the earthworks remains, built to a contemporary specification and standing on land contributed from the estate of Sir Henry Vaughan, still is visible today even though masked from public view by the vandalistic edifice of the local Tesco Stores. Recent archaeological work has also shown that the towers of the Medieval Castle, which formed part of the circuit, were modified to mount cannon to command the Bridge over the river Towy After a fierce assault on the Gate at nearby Lammas Street, Sir Henry was forced to retreat from Carmarthen Town for a while but it was back in Royalist control the next year.

By then Sir Henry had returned to the Oxford Army, where his Regiment served as part of Lisle's Tertio, initally at Reading Garrison, and later at Cheriton , the Lostwithiel Campaign and Second Newbury. On 26 April, part of the regiment, under command of Henry Vaughan the younger, was attacked at Bampton in the Bush, 18 miles west of Oxford, by Oliver Cromwell.

Despite their sturdy defence, it seems that the next morning, these isolated soldiers surrendered, perhaps due to lack of powder and shot after the night attacks, and perhaps 200 of them were taken prisoner.

Vaughan the younger presumably took part in the Skirmish at Llandeilo in April 1648 where the Royalist Insurgents defeated elements of the New History of the original regiment: Sir Henry Vaughan of Derwydd, near Llandeilo, Carmarthenshire, was a younger brother of the First Earl of Carbery, John Vaughan of Golden Grove. By the time of the Civil War, the Vaughan's of Golden Grove were the dominant landowner in Carmarthenshire. Henry's nephew, Richard Vaughan had inherited the earldom in 1634, and soon after the outbreak of the Civil war Richard was appointed the Kings Lieutenant General in South Wales.Model Army, no less a person than the Agitant General of the New Model, Colonel Fleming, being killed in the process A month later, he was made prisoner together with 48 of his men while trying to cross Snowdonia to join Sir John Owens force's, and was then confined to Denbigh Castle, this marking the end of the Civil War career of the Vaughans

. Sir Henry the elder was released from prison by Parliament in 1659, and he died shortly before 5 January 1660/1

Although the regiment itself does not appear to have taken part in the battle of Naseby, Sir Henry himself was wounded in the fight and made prisoner. He was one of the Royalist prisoners in the Tower.