Jiangnan's alluvial lands make the region, especially Jiangsu, one of the richest and most populous countries of China.
The Jesuit priest Matteo Ricci was its first missionary, introducing the Catholic religion into this country at the end of the 16th century.
He found a powerful aid in the person of the Kangxi Emperor's minister, the academician Xu Guangqi, whom he met first at Guangdong and later at Beijing.
Baptized in 1603 at Nanjing, Paul Xu returned to Shanghai, his native place, and there converted many Chinese to Catholicism.
The Jesuits Francesco Brancati and Geronimo de Gravina were at this period building the churches of Sun-kiang, Suzhou and Chongming; Sambriani, those of Nanjing, Yangzhou and Huai'an.
In 1660 the Vicariate Apostolic of Jiangnan was created and confided to Bishop Ignace Cotolendi of the Paris Society of Foreign Missions.
In 1690 Alexander VIII created the Diocese of Nanjing, placing it under the jurisdiction of the (Portuguese Indian) Archbishop of Goa and with authority over the provinces of Jiangnan and Henan.
Three Jesuit missionaries followed in Jiangnan: Ignatius Perez, Martin Correa and Godefroy of Lambeckhoven, named Bishop of Nan-king on 15 May 1752, and consecrated at Macau on 22 July 1756.
He remained thirty years at Jiangnan with two Chinese Jesuit priests, Mark Kwan and John Yau.
He arrived at Jiangnan in 1842, and obtained some French Jesuits from Propaganda Fide, and from Roothan, then General of the Society of Jesus.
They made the voyage with Marie Melchior Joseph Théodore de Lagrené, ambassador of France to Beijing, who in 1844 obtained permission in the Treaty of Whampoa for the preaching of the Catholic religion in China.
Bishop de Besi appointed Brueye to found the seminary, which was opened on 3 February 1843, with twenty-three students.
In 1849 the latter was named administrator of the Diocese of Nanjing, but returned to Europe, owing to ill health, on 8 April 1855.
During the eight years of his administrator ship the rebels laid waste all the Christian missions of Jiangnan except that of Shanghai.
Massa was arrested by them but made his escape; his brother Louis, however, was killed by defending the orphanage of Tsai-kia-wan.
He founded the observatory about the same period, and took part in the First Vatican Council in 1870, but in 1874 a stroke of apoplexy almost disabled him for any active service.
On 5 February 1889, the European concession of Jinjiang was attacked by the Chinese, the consulate of the United States was pillaged and burned, but the church and residence of the mission was spared.
Bishop Simon was named Vicar Apostolic in January 1899, and consecrated on 25 June; he died on 25 Aug. of the same year at Wuhu.