At the age of 43 his petition to be a missionary in China was accepted. His first post was one of the most destitute Christian settlements in China.

For several years, Father Francis endured abuse and attacks which frequently forced him to find refuge in the mountains. In spite of these difficulties, he succeeded in keeping up the fervor of the Christians and bringing many pagans to the fold. In 1819, Francis and a Chinese confrere became fugitives. He was finally betrayed by a Catholic schoolmaster. Francis was forced to march in chains over hundreds of miles. On January 1, 1820, Francis was found guilty of deceiving the Chinese people by preaching Christianity. On February 18, 1820 he was tied to a stake erected like a cross, and was strangled to death. He was canonized a saint on October 1, 2000.