that typified the continental Baroque and employed a wide range of different forms of steeple, experimental efforts to find a substitute for the Gothic spire within a Classical mode. However, a dome featured very prominently in Wren's grandest construction, St Paul's Cathedral, the only English cathedral in any permutation of the Classical tradition. The later 17th century saw Baroque architecture, a version of Classicism characterised by heavy massing and ostentatiously elaborate decoration, become widespread in England. Grand Baroque country houses began to appear in England in the 1690s, exemplified by Chatsworth House and Castle Howard. The most significant English Baroque architects after Wren were Sir John Vanbrugh and Nicholas Hawksmoor, who adapted the Baroque style to fit English tastes in houses such as Blenheim Palace, Seaton Delaval Hall and Easton Neston. Georgian architecture The 18th century saw a turn away from Baroque elaboration and a reversion to a more austere approach to Classicism. This shift initially brought a return to the Italian Palladianism that had characterised the earliest manifestations of Classical architecture in England. Later Neoclassical architecture increasingly idealised ancient Greek forms, which were viewed as representing Classicism in its original "purity", as against Roman forms. Country houses representing this style include Woburn Abbey and Kedleston Hall. This period also saw the emergence of an increasingly planned approach to urban expansion, and the systematic, simultaneous construction of whole streets or squares, or even of entire districts, gave rise to new forms of domestic construction, the terrace and the crescent, as exemplified in Bath and in Bloomsbury and Mayfair in London. Among the notable architects practising in this era were Robert Adam, Sir William Chambers, John Wood and James Wyatt. Victorian architecture The 19th century saw a fragmentation of English architecture, as Classical forms continued in widespread use but were challenged by a series of distinctively English revivals of other styles, drawing chiefly on Gothic, Renaissance and vernacular traditions but incorporating other elements as well. This ongoing historicism was counterposed by a resumption of technical innovation, which had been largely in abeyance since the Renaissance but was now fuelled by new materials and techniques derived from the Industrial Revolution, particularly the use of iron and steel frames, and by the demand for new types of building. The rapid growth and urbanisation of the population entailed an immense amount of new domestic and commercial construction, while the same processes combined with a