[5] On his return to England, apparently possessing at least Rossi's first volume (of 1702), Shrewsbury called upon Archer to create a modern Italian palazzo set in the Oxfordshire countryside.

At this time, Archer was one of the few English architects to have studied in Italy and become conversant with the Baroque forms of architecture,[2] but many of the details of Heythrop[6] were adapted from Roman precedents through engravings in Rossi's publication, though none was directly imitated.

By 1709 the roof was in place and by 1713 the house was ready for partial occupation, but John Vanbrugh noted in April 1716 that it was incomplete,[7] and so it was still, on Shrewsbury's death in 1718.

On the entrance facade of eleven bays, the giant order with a level balustraded roof is very similar to the design which William Talman had executed for the Duke of Devonshire at Chatsworth House just few years earlier.

In 1831 a fire swept through the house destroying the interiors,[2] many designed by James Gibbs, including a quatrefoil hall, a feature believed to have been unique in England.

Other features of the rooms included a saloon which had an entablature supported by life-sized statues of Ceres and Flora beneath a stuccoed ceiling depicting the four corners of the globe.

Waterhouse, a noted Gothic Revival architect, in deference to the history of the house worked in a neo-classical style; his double-height arcaded hall, being more redolent of the Baroque of John Vanbrugh than Archer.

[11] However, Waterhouse did add Gothic motifs to the hall's clerestory in the form of stained glass windows, by Morris and Co, depicting Faith, Hope and Charity.

[15] When in 1970 the Jesuit college moved to London as part of the University there, the National Westminster Bank group bought Heythrop Park and turned the house and its precincts into a training and conference centre.