Alopen (, ; also "Aleben", "Aluoben", "Olopen," "Olopan," or "Olopuen") is the first recorded Assyrian Christian missionary to have reached China, during the Tang dynasty. He was a missionary from the Church of the East (also known as the "Nestorian Church"), 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.
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 thinks his name could be a transcription of "Ruben".
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.
太宗文皇帝,光華啓運,明聖臨人,大秦國有上徳曰阿羅本,占青雲而載真經,望風律以馳艱險。貞觀九祀,至扵長安。
In the time of the accomplished Emperor Taitsung, the illustrious and magnificent founder of the dynasty, among the enlightened and holy men who arrived was the Most-virtuous Olopun, from the country of Syria. Observing the azure clouds, he bore the true sacred books; beholding the direction of the winds, he braved difficulties and dangers. In the year AD 635 he arrived at Chang-an.
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.