The castle was built on land previously owned by the St Martin family, but when Sir Lawrence de St Martin died in 1385 it was handed over to John, the fifth Baron Lovell, for reasons unknown. It was built using locally quarried Tisbury greensand, with William Wynford as the master mason, after Baron Lovell had been granted permission by Richard II in 1392. It was inspired by the hexagonal castles then in fashion in parts of the Continent, particularly in France; but its own six-sided design is unique in Britain, as is its inclusion of several self-contained guest suites.
After the fall of the Lovell family following their support of the Lancastrian cause during the Wars of the Roses, the castle was confiscated in 1461 and passed through several owners until bought by Sir Thomas Arundell of Lanherne in 1544. The Arundells were an ancient and prominent Cornish family, the principal branches of which were seated at the manors of Lanherne, Trerice, Tolverne and Menadarva in Cornwall. The family held several estates in Wiltshire.