大秦景教流行中国碑
Alopen's name is known only from the Chinese of the Nestorian Stele. This may be a transliteration of the Semitic "Abraham" or "aloho punoya," "the conversion of God." According to the Stele, Alopen and his fellow missionaries came to China from Daqin (or Ta Tsin – the Byzantine Empire) in the ninth year of Emperor Taizong (Tai Tsung; 635), bringing sacred books and images. He would have come to China via the Silk Road. The Nestorian mission benefited from Taizong's policy of religious tolerance, which reversed measures his father Gaozu had taken against Buddhism and other foreign religions and influences.