Gerard Houckgeest, followed by van Witte and Hendrick van Vliet, had supplemented the traditional view along a main axis of the church with diagonal views that added drama and interest. Gerrit Berckheyde specialized in lightly populated views of main city streets, squares, and major public buildings; Jan van der Heyden preferred more intimate scenes of quieter Amsterdam streets, often with trees and canals. These were real views, but he did not hesitate to adjust them for compositional effect. Maritime painting The Dutch Republic relied on trade by sea for its exceptional wealth, had naval wars with Britain and other nations during the period, and was criss-crossed by rivers and canals. It is therefore no surprise that the genre of maritime painting was enormously popular, and taken to new heights in the period by Dutch artists; as with landscapes, the move from the artificial elevated view typical of earlier marine painting was a crucial step. Pictures of sea battles told the stories of a Dutch navy at the peak of its glory, though today it is usually the more tranquil scenes that are highly estimated. Ships are normally at sea, and dock scenes surprisingly absent. More often than not, even small ships fly the Dutch tricolour, and many vessels can be identified as naval or one of the many other government ships. Many pictures included some land, with a beach or harbour viewpoint, or a view across an estuary. Other artists specialized in river scenes, from the small pictures of Salomon van Ruysdael with little boats and reed-banks to the large Italianate landscapes of Aelbert Cuyp, where the sun is usually setting over a wide river. The genre naturally shares much with landscape painting, and in developing the depiction of the sky the two went together; many landscape artists also painted beach and river scenes. Artists included Jan Porcellis, Simon de Vlieger, Jan van de Cappelle, Hendrick Dubbels and Abraham Storck. Willem van de Velde the Elder and his son are the leading masters of the later decades, tending, as at the beginning of the century, to make the ship the subject, whereas in tonal works of earlier decades the emphasis had been on the sea and the weather. They left for London in 1672, leaving the master of heavy seas, the German-born Ludolf Bakhuizen, as the leading artist. Still lifes Still lifes were a great opportunity to display skill in