They were the largest kitchens in the Ottoman Empire. Food was prepared for about 4,000 people and the kitchen staff consisted of more than 800 people. The kitchens included dormitories, baths and a mosque for the employees, most of which disappeared over time. Apart from exhibiting kitchen utensils, today the buildings contain a silver gifts collection, as well as a large collection of porcelain. The Ottomans had access to Chinese porcelains from the mid-fifteenth century onward. The collection of 10,700 pieces of Chinese porcelain is among the finest porcelain collections in the world. Porcelains often entered the palace collection as parts of the estates of deceased persons, and were sometimes circulated as gifts amongst members of the royal family or other leading officials. Records indicate that by the 18th century the palace collection had 16,566 pieces of Chinese porcelain, compared to 400 pieces in the 16th century and 3,645 pieces in the 17th century. The Chinese porcelain collection ranges from the late Song Dynasty (960-1279) and the Yuan Dynasty (1280–1368), through the Ming Dynasty (1368–1644) to the Qing Dynasty (1644–1911). The pieces include celadons as well as blue and white porcelain. The Japanese collection is mainly Imari porcelain, dating from the 17th to the 19th centuries. The collection also includes around 5,000 European pieces. Researchers believe that Ottoman tastes changed over time to favor various types of European porcelain by the 18th century. The Imperial Council ("Dîvân-ı Hümâyûn") building is the chamber where the Imperial Council—consisting of the Grand Vizier ("Vazīr-e Azam") and other council ministers ("Dîvân Heyeti")—held meetings. The domed chamber of the building is called "Kubbealtı", which means "under the dome". The council building situated in the northwestern corner of the courtyard next to the Gate of Felicity. The Imperial Council building was first built during the reign of Mehmed II. The present building dates from the period of Süleyman the Magnificent; the chief architect was Alseddin. It had to be restored after the Harem fire of 1665. According to the entrance inscription it was also restored during the periods of Selim III and Mahmud II; on its façade are verse inscriptions that mention the restoration work carried out in 1792 and 1819 by Sultan Selim III and Mahmud II.