As rulers of the cultural superior realm of China, the Qing emperors adopted the state doctrine of Confucianism as their official religion. The emperor underwent all sacrifices for Heaven (at the Altar of Heaven Tiantan 天壇 in Beijing), Earth, and his ancestors. Confucius was venerated as the greatest of the Saints. Indeed, the most of the buildings of Confucius' home court in Qufu 曲阜/Shandong were erected during the Qing Dynasty. Daoism lived as a popular religion since the advent of Buddhism. and was accepted as one of the Three Religions of China (Sanjiao 三教: Confucianism Rujiao 儒教, Daoism Daojiao 道教, and Buddhism Fojiao 佛教). Like the Mongol rulers, the Qing emperors who had made an alliance with the Mongols, followed Tibetian Lamaism as a special religion because of political reasons: The Tibetian rulers accepted the nominal Qing sovereignity over Tibet, but they wanted to have Lamaist monasteries in Beijing and a Tibetian ambassador staying in the Qing capital. Islam (Yisilanjiao 伊斯蘭教) was widespread among the population of Chinese Turkestan, but also in many cities throughout China. This foreign religion had no importance throughout Chinese history until the middle of the 19th century. Christianity had made first steps during the end of Ming Dynasty. The Jesuit patres and court astronomers Adam Schall von Bell (Chinese: Tang Ruowang 湯若望) and Ferdinand Verbiest could win the confidence of the Shunzhi and Kangxi Emperors. Bell introduced the solar calendar to China with a 365 day year and 7 day weeks. Like Matteo Ricci, they tried to win the imperial court and the highest elite for Christianity without touching Chinese customs and beliefs, like ancestor veneration and state sacrifices to Heaven. Many performances of Catholic religion indeed resembled Buddhist practices, like incantations, bells, ceremonial prayers, processions, pictures, relics, and so on. The Vatican tried to obviate the missionary way of the Jesuits in China. The theological reason was that the Chinese did not believe in immaterial substances that can be separated from matter, and that they did not see a difference between natural order and human moral law. The downfall of Christianity in China came when the Kangxi Emperor decided that the Jesuits - being his own officials - could not obey orders from Rome. In 1773, the Jesuit order was dissolved worldwide. If we believe in the sources, some 100,000 Christians may have lived in China at the end of the 17th century. French and American missionaries would be the next, but their way to convert the Chinese would be a very different one.