Alopen (, ; also "Aleben", "Aluoben", "Olopen," "Olopan," or "Olopuen") is the first recorded Christian missionary to have reached China, during the Tang dynasty. He was a missionary from the Church of the East, and probably a Syriac speaker from the Sasanian Empire or from Byzantine Syria. He is known exclusively from the Xi'an Stele, which describes his arrival in the Tang capital of Chang'an in 635 and his acceptance by Emperor Taizong of Tang. His is the earliest known name that can be attached to the history of the Church of the East in China.
History
thumb|right|Detail of the [[Xi'an Stele artifact, mentioning Alopen]]
Alopen's name is known only from the Chinese of the Xi'an Stele. This may be a transliteration of the Semitic "Abraham" or aloho punoya, "the conversion of God." Amy Chua posits that his name could be a transcription of "Ruben", Alexis Balmont rather advocates for Ardaban.
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 Church of the East 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.
According to the Stele, Taizong welcomed Alopen and arranged for the translation of the holy writings he had brought with him at the Imperial Library. Upon studying them, Taizong, a great scholar and patron, found them most acceptable and arranged for their dissemination. Indeed, four documents from the early period of Christianity in China date to around Alopen's time.
After Alopen's time, the Church of the East was prominent in China for the remainder of the Tang Dynasty's power. Different emperors treated it differently, with some showing it the tolerance it received in the early decades, and some openly persecuting it. The Church of the East disappeared with the fall of the Tang Dynasty in the early 10th century. It did not return for three centuries, when it was reintroduced by the Mongols.