Gothic palazzi, which had evolved to suit Venetian conditions. In turn the transition to Baroque architecture was also fairly gentle. This gives the crowded buildings on the Grand Canal and elsewhere an essential harmony, even where buildings from very different periods sit together. For example, round-topped arches are far more common in Renaissance buildings than elsewhere. Rococo style It can be argued that Venice produced the best and most refined Rococo designs. At the time, the Venetian economy was in decline. It had lost most of its maritime power, was lagging behind its rivals in political importance, and its society had become decadent, with tourism increasingly the mainstay of the economy. But Venice remained a centre of fashion. Venetian rococo was well known as rich and luxurious, with usually very extravagant designs. Unique Venetian furniture types included the divani da portego, and long rococo couches and pozzetti, objects meant to be placed against the wall. Bedrooms of rich Venetians were usually sumptuous and grand, with rich damask, velvet, and silk drapery and curtains, and beautifully carved rococo beds with statues of putti, flowers, and angels. Venice was especially known for its beautiful girandole mirrors, which remained among, if not the, finest in Europe. Chandeliers were usually very colourful, using Murano glass to make them look more vibrant and stand out from others; and precious stones and materials from abroad were used, since Venice still held a vast trade empire. Lacquer was very common, and many items of furniture were covered with it, the most noted being lacca povera (poor lacquer), in which allegories and images of social life were painted. Lacquerwork and Chinoiserie were particularly common in bureau cabinets. Glass Venice is known for its ornate glass-work, known as Venetian glass, which is world-renowned for being colourful, elaborate, and skilfully made. Many of the important characteristics of these objects had been developed by the 13th century. Toward the end of that century, the centre of the Venetian glass industry moved to Murano, an offshore island in Venice. The glass made there is known as Murano glass. Byzantine craftsmen played an important role in the development of Venetian glass. When Constantinople was sacked in the Fourth Crusade in 1204, some fleeing artisans came to Venice; when the Ottomans took Constantinople in 1453, still more glassworkers arrived. By the 16th century, Venetian artisans had gained even greater control over the colour and