The main part of the site consisted of two rectangles of land. The smaller of these was towards Oxford Street. There, the main doorway, sheltered by a
portico, and the two side doorways opened to a vestibule, wide and deep, which was divided by screen colonnades into three compartments. A central set of doors opened into the first of two card rooms, and two further pairs of doors opened onto corridors or galleries, giving access to the grand staircase and the great assembly room or rotunda. The total depth of the site was and the maximum width was . There is general agreement that the scheme of the great room, or rotunda, was derived from
Santa Sophia in
Istanbul. The central space was contained in a square of topped by a
coffered
dome. On the east and west sides were superimposed
colonnades of seven bays, screening the aisles and first floor galleries. At the north and south end there were short arms, wide, terminating in shallow segmental
apses. The architectural elements and decorations were strictly
Roman in inspiration. Below the rotunda there was a tea and supper room, of the same shape but divided into five aisles by the piers supporting the floor above. The architecture of the Pantheon was lavishly praised by many of those who saw it.
Horace Walpole compared Wyatt's work favourably with that of better established and very fashionable
Robert Adam, "the Pantheon is still the most beautiful edifice in England" he said.
Dr. Burney, writing long after the destruction of the original building by fire (an event which inflicted on him a heavy financial loss), stated that the Pantheon "was built by Mr. James Wyatt, and regarded both by natives and foreigners, as the most elegant structure in Europe, if not on the globe… . No person of taste in architecture or music, who remembers the Pantheon, its exhibitions, its numerous, splendid, and elegant assemblies, can hear it mentioned without a sigh!" Contemporary reports of the cost of the building were greatly exaggerated. Writing to Sir
Horace Mann in May 1770 Horace Walpole asked "What do you think of a winter Ranelagh erecting in Oxford Road, at the expense of sixty thousand pounds?". The courts later determined that the actual cost was £36,965 19s. 5½d: £27,407 2s. 11½d for the main construction work, £2,500 for the entrance from Poland Street and £7,058 16s. 6d for furniture, paintings, statues, the organ, and Wyatt's five per cent commission as architect. ==History==