Castle Ashby House is one of the seats of the Marquess of Northampton.
The original castle, a manor house, came about as the result of a licence obtained in 1306, by Walter Langton, Bishop of Coventry, to castellate his mansion in the village of Ashby. Sir Gerard Braybroke was at one time of Castle Ashby Manor. It is a leading example of the Elizabethan prodigy house, with a Palladian section closing the front courtyard added in the 18th century.
The present rebuilding of Castle Ashby was started by Henry Compton, 1st Baron Compton, in 1574 and was continued by his son, created Earl of Northampton. Queen Elizabeth I's first visit to the house was in 1600. Like other houses of its date, it was built in an E-shaped floorplan, a deep central porch and flight of steps forming the centre stroke of the E. This was to celebrate the coronation of Queen Elizabeth I. When King James and his Queen first stayed in 1605, the castle is documented as "Lord Compton's princely mansion", and in the household records we find that employed at this time were 83 household servants, four chaplains, three musicians and the Gardener of Ashby.
The parapet of stone lettering around the top of the house is dated 1624, and its Latin inscription runs as follows:
The words are based on the 127th Psalm, "Except the Lord build the house they labour but in vain they who build it; except the Lord keep the house the watchman waketh but in vain".
By 1635 an ambitious classicising screen had been added across the open southern side of the courtyard, probably to make the two wings directly accessible to each another; its design deviates enough from Palladian canons to make it unlikely that Inigo Jones designed it;Howard Colvin suggested that a payment of £8 to "Cartor Surveyor" in the Earl's accounts, September 1631, may refer to Edward Carter, Jones's deputy at St. Paul's Cathedral, 1633-41. Work proceeded at Castle Ashby until, as Colen Campbell the architect put it, "the Civil Wars put a stop to all Arts".