The manor, together with the borough and hundred, passed into the de Redvers family on the death of Warin FitzGerold the younger in 1216. His only child, Margaret or Margery, had married Baldwin de Redvers, Earl of Devon, in about 1215. They stayed in the family until Isabel de Forz passed them to Adam de Stratton in November 1276. On his disgrace in 1289 his lands and goods were forfeited to the Crown. From this time it is unlikely that few of its lords came near it. During that period it was administered by keepers for Margaret, the second wife of Edward; Isabel, the widow of Edward II; Phillippa, widow of Edward III; John de Montfort, duke of Brittany; Edmund, duke of York; his second son Edward; Cicely, duchess of York, who was mother of Edward IV; Elizabeth, queen to Henry VI; Catherine of Aragon; Jane Seymour; Anne of Cleeves and Catherine Howard. Sir Thomas Seymour acquired the manor in 1541 and the following year this passed to John Warneford. It was at about this time that its association with the borough and hundred appears to have ended.
The borough and hundred of Highworth continued in the king's hand until 1544, when they were granted to Queen Catherine Parr for life as part of her dower on her marriage to King Henry VIII. The reversion was granted in 1547 to Sir Thomas Seymour, now baron Seymour of Sudeley, who married the widowed queen. When he was attainted in 1549 they reverted to the crown.
In the reign of Queen Elizabeth, Sir Richard Grobham of Great Wishford owned the Borough and Hundred of Highworth. Sir Richard had made a very large fortune as steward to the George family of Longford Castle and he and Sir Thomas George had shared in the Treasure ship of the Spanish Armada.
Sir Richard died childless in 1628 and left his estate to his sister's son, afterwards Sir John Howe Bt, and it remained in the family until 1804 and the death of John Howe, 4th and last Lord Chedworth, from whose trustees they were purchased in 1806 by Mr Wm Crowdy, a solicitor of Highworth, who had built and occupied Westrop House. His descendant Mr Robert Edward Laurence Crowdy sold the estate to John Kenney in 1969. By this time there were no pecuniary rights other than the ownership of several houses in the Borough including the three interesting old stone built houses at the East end of the High Street now remodelled into
1 - 5 the High Street.
In the first half of the 17th century outbreaks of plague had occurred in Highworth and the surrounding area. The Civil War of 1642-1649 caused enormous upheaval throughout the country involving towns in great distress and disruption to both their economic and social life.
By 1643 traders coming to Highworth's cattle markets were experiencing difficulties caused by the Royalists quartered in the area and in the September of that year the townspeople were under pressure to accommodate the sick and wounded from the siege of Cirencester.
The royalist, Major General Astley decided to fortify Highworth in April 1644. The church was selected as a strong point. St Michael's tower provides an excellent lookout over the Thames valley and a lofty firing platform. The fortifications were not started until December of 1644 and appear to consist of an earth work bank and ditch about six feet wide, which included an arrow shaped projection called a bastion from which flanking fire could be given. This is thought to run under the present Methodist Church Hall to the north of the church running in an east - west direction. The town was then given a permanent garrison of around 200 men, under Major Henry Henne who was appointed, by the King, as governor of Highworth on the 10th January 1645. They would not be there for very long.