Camillus Costanzo was an Italian Jesuit missionary who served in Japan during the early 17th century. Born in Bovalino in 1571, he initially studied law and served as a soldier before joining the Society of Jesus. Although he originally intended to travel to China, he was redirected to Japan, where he quickly mastered the local language. He worked to support Catholic converts near Sakai until the Tokugawa shogunate's restrictive laws forced him to flee to Macau.