The next great architect of this period is Sir John Vanbrugh, who, when in the zenith of his fame as a dramatic writer, suddenly started forth as an architect, and had the honour of erecting Castle Howard, the seat of the Earl of Carlisle; Blenheim House, built for the Duke of Marlborough, in reward of his victories; Duncomb Hall, Yorkshire; King's Weston, in Gloucestershire; Oulton Hall, Cheshire; Grimsthorpe, in Lincolnshire; Eastbury, in Dorsetshire, now destroyed; and Seaton Delaval, in Northumberland, since partly destroyed by fire. Besides these, he built the opera house, also destroyed by fire. In all these there is a strong similarity, and as a general effect, a certain magnificence; but, when examined in detail, they too frequently resolve themselves into a row of individual designs merely arranged side by side. This is very much the case with the long façade of Blenheim. There is a barbaric splendour, but it has no pervading unity, and only differs from the Italian manner of Wren by a much bolder and profuser use of the Grecian columns and pilasters. In fact, the architecture of the whole of this period is of a hybrid character, the classical more or less modified and innovated to adapt it to modern purposes and the austerity of a northern climate. Amongst the most distinguished of this series of architects is James Gibbs, who, after studying in Italy, returned to England in time to secure the erection of some of the fifty churches ordered to be built in the metropolis and its vicinity in the tenth year of Queen Anne. The first which he built is his finest--St. Martin's, at the north-east corner of Trafalgar Square. Besides St. Martin's, Gibbs was the architect of St. Mary's, in the Strand; of Marylebone Chapel; of the body of All Saints', Derby--an incongruous addition to a fine old Gothic tower; of the Radcliffe Library, at Oxford; of the west side of the quadrangle of King's College, and of the Senate House, Cambridge, left incomplete. In these latter works Sir James Burrows, the designer of the beautiful chapel of Clare Hall, in the same university, was also concerned. Gibbs was, moreover, the architect of St. Bartholomew's Hospital. Nicholas Hawksmoor, a pupil of Wren's, and an assistant of Vanbrugh's in building Castle Howard and Blenheim House, was the architect of St. George's-in-the-East, Ratcliff Highway, begun in 1715; of St. Mary Woolnoth, Lombard Street; of St. George's, Bloomsbury; St. Anne's, Limehouse; of Easton Norton House, in Northamptonshire; and of some other works, including a mausoleum at Castle Howard, and repairs of the west front of Westminster Abbey. St. George's, Bloomsbury, is perhaps his finest structure. It has a Corinthian portico, like St. Martin's, and the steeple is surmounted by a statue of George II.