What is "alopen"

Alopen ( pinyin: Āluóběn; 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 (also known as the Nestorian Church), and probably a Syriac-speaker from the Persian Empire, or from Syria in the Byzantine Empire. He is known exclusively from the Nestorian Stele, which describes his arrival in the Chinese capital of Chang-an in AD 635 and his acceptance by Emperor Taizong. His is the earliest known name that can be attached to the history of Nestorianism in China.