Most of the gentry at this time, as John Webb tells us, had some knowledge of the theory of architecture, “but nothing of ye practicque.” Roger Pratt bettered his fellows in this respect, for not only had he a wide knowledge of the art, as understood in the seventeenth century--of the architecture, that is, of modern Italy and of Palladio in particular--but he was familiar with the qualities of materials and the routine of building, not to mention tactful methods of accounting for “extras.” During his stay in Rome he met John Evelyn, who appears to have acquired and preserved a high regard for him. Twenty years later, in writing to Lord Cornbery on 20th January 1665, about his father’s mansion of Clarendon House, Evelyn said that Roger Pratt, his old friend and fellow traveller (co-habitant and contemporary at Rome), had “perfectly acquitted himself.” The turn of events had brought them together about this time, when both of them became commissioners for the repair of St Paul’s Cathedral and for the rebuilding of London after the great fire. Pratt’s chief works were Horseheath in Cambridgeshire for Lord Allington, and Clarendon House. The former was begun in 1663, and was a magnificent mansion. There are many technical notes relating to it in the note-books, but not much of general interest beyond its dimensions. It was dismantled in 1760, and sold for the value of the materials. The notes concerning Clarendon House, which was begun in 1664, are more voluminous. They serve to show that Pratt was a practical architect, that he was fully acquainted with the details of the various trades, and was alive to the chances of crooked dealing by the workmen. He deals with the levels of the site and the setting out of the house, which was to be placed central with St James’s Street, truly parallel with the frontage line, and set back 160 ft., whereby a court of that depth and of a width of 214 ft. would be obtained. Another lively touch is given by his instructions to the mason regarding the coat of arms in the tympanum of the “frontispiece,” the central feature of the front. The description which he incidentally gives agrees with what is shown on the engraving. But more interesting and more entertaining are the reasons he adduces in a draft letter of the 13th February 1665 (1666 new style) to the Lord Chancellor for the cost having exceeded his estimate. The foundations were much deeper than was expected, an old pond having been found on one part of the site, and a vast hole the whole length of my lady’s pavilion on another. Severe frost rendered it necessary to take down and rebuild some of the work. My Lord Cornbery caused a foot to be added to the height of the first floor, much increasing, it is true, the nobleness of the effect. The bricks cost more; the Dutch war increased the price of timber, and the carpenter threw up his contract, leaving himself to the mercy of his employer; but the plague had infected the whole town, and workmen everywhere