In 1602, he published a world map, the K'un-yu Wan-kuo Ch'uan T'u, which included the latest information available to Europeans--such as the existence of America.
利瑪竇原在羅馬大學攻讀法律，進了耶穌會以後，入羅馬神哲學院改讀哲學，兼習數學、天文、地理… …，因此他的科學知識相當豐富。