Xu Guangqi or Hsü Kuang-ch'i (April 24, 1562– November 8, 1633), also known by his baptismal name Paul, was a Chinese agronomist, astronomer, mathematician, politician, and writer during the Ming dynasty. Xu was appointed by the Chinese Emperor in 1629 to be the leader of the ShiXian calendar reform, which he embarked on with the assistance of Jesuits. Xu was a colleague and collaborator of the Italian Jesuits Matteo Ricci and Sabatino de Ursis and assisted their translation of several classic Western texts into Chinese, including part of Euclid's Elements. He was also the author of the Nong Zheng Quan Shu, a treatise on agriculture. He was one of the "Three Pillars of Chinese Catholicism"; the Roman Catholic Church considers him a Servant of God. On April 15, 2011, Vatican spokesman Federico Lombardi announced the beatification of Xu Guangqi. Name Xu Guangqi is the pinyin romanization of the Mandarin Chinese pronunciation of Xu's Chinese name. His name is written using the Wade–Giles system. His courtesy name was Zixian and his penname was Xuanhu. In the Jesuits' records, it is the last which is used as his Chinese name, in the form At his conversion, he adopted the baptismal name Paul (). In Chinese, its transcription is employed as a kind of courtesy name (i.e., Xu Baolu) and the Jesuits sometimes referred to him as or . More often, however, they describe him as "Doctor Paul" (; ), "Our Paul" (), or "Paul Siu" or "Ciu". Early life Xu Guangqi was born in Shanghai in Southern Zhili's Songjiang Prefecture on April 24, 1562, under China's Ming dynasty. At the time, Shanghai was merely a small walled county seat in the old quarter around the present city's Yu Garden. His family, including an older and younger sister, lived in the Taiqing Quarter at the south end of the town. Guangqi's branch of the Xus were not related to those who had passed the imperial examinations and joined Shanghai's local gentry. His father (died) had been orphaned at age 5 and seen most of his inheritance lost to "Japanese" pirate raids and insolvent friends in the 1550s. At the time of Guangqi's birth, his father worked twenty mu (1¼ha) or less south of the city wall. About half of this would have been used to feed the family, with the rest used to supplement his income from small-scale trading. By the time Guangqi