P’yŏngan-namdo
He was a member of the Indong Chang Family (인동장씨;仁同張氏), and descended from Jukjong Chang Cham (죽정장잠;竹亭張潛), a well-known Neo-Confucianism philosopher. Chang's ninth-generation grandfather lived in South Pyongan Province Province but his father moved to Incheon. The first Roman Catholic believer in his family was his great-grandmother, Lady Park.