When Inigo Jones built his portico, he cased the nave with Portland stone, and rebuilt the north and south fronts. In doing so he pared down the original pointed architecture, until little of its beauty or character remained. His work had in its turn been damaged by the Puritans, who set up booths in the portico, and dug sawpits in the cathedral inclosure. Besides these injuries Christopher Wren's accurate eye detected graver faults in the original design, some of which he enumerates. 'The pillars of the nave, though eleven feet in diameter, were only cased with stone, and filled up with rubbish inside. The roof was always too heavy for them, so that they are bent outwards on both sides, so that the roof already cracked will finally fall in.' He proposed to substitute a roof[97] of 'a light, thin shell of stone, very geometrically made.' The tower leant much to one side, and was propped with arches and buttresses, so as to block the view from the west end. Upon this tower, which he despairingly calls 'a heap of deformities,' there had been formerly a tall, thin, wooden spire, which was destroyed by lightning. For this he wished to substitute 'a dome or rotunda, and upon the cupola for outward ornament, a lantern with a spring top to rise proportionately.' He hints that when the dome was finished the rest of the cathedral should be harmonised with it, almost impossible though the task appeared. He expected great difference of opinion, and that 'some would aim at a greater magnificence than the age would afford, and some might fall so low as to think of piecing up the old fabric here with stone, there with brick, and covering all faults with a coat of plaster, to leave it still to posterity as an object of charity.' The miserable state of the building is implied in the epitaph of its Dean, Dr. Barwick, who in 1664, 'Inter sacras Ædis Paulinæ ruinas reponit suas (utrasque resurrecturas securus)'.[98] [_SHELDONIAN THEATRE._] Another work upon which Wren was engaged was the Sheldonian Theatre at Oxford. Sheldon, who succeeded Archbishop Juxon in the see of Canterbury in 1663, was determined to free S. Mary's Church from the profane uses to which it was put when the various 'Acts' were kept there, and any kind of jesting and buffoonery was considered allowable. He had had experience of Wren in the discussions about S. Paul's, and now engaged him as architect. The building is too well known to need a description; the roof was reckoned a triumph of skill because of 'the contrivance of supporting the same without the help of any beam, it being entirely kept up by braces and screws; and is the subject of an excellent mathematical treatise by that prodigy of the age, Dr. Wallis.'[99] It was six years building, and cost 25,000_l._ Evelyn, with whom Wren had often discussed the plans, went to Oxford on purpose to be present at the opening on July 9, 1669.