Origins and Call to the Episcopate
Orthodox tradition, as preserved in the synaxarion and recorded on OrthodoxWiki, holds that Gregory came from Mediolanum (Milan) in the sixth century, the son of devout parents named Agapios and Theodotia. He was noted early for his eloquence and virtue, and according to the tradition possessed gifts of healing and wonderworking from his youth.
While serving as a deacon at Milan, he is said to have been directed toward his future calling through a series of visions, after which he traveled to Rome, Constantinople, and Alexandria. At Alexandria the patriarch ordained him priest and then consecrated him bishop, sending him to serve in the territory recently brought under Christian rule. (A scholarly Life based on the manuscript tradition instead places his birth in Pannonia rather than Milan; the synaxarion tradition of an Italian origin is followed here.)
Mission Among the Homerites
Gregory's episcopate fell in the aftermath of the persecution of Christians in Himyar under the Jewish king Dhu Nuwas, whose massacre of the Christians of Najran (traditionally dated 523) prompted Byzantine appeals for Ethiopian (Aksumite) intervention. After the Aksumite king Elesbaan (Kaleb Ella Asbeha) defeated Dhu Nuwas around 525, Gregory was sent to organize the Church in the region.
As archbishop of Zafar (Taphar), the Himyarite capital, he served for about thirty years, assisting the viceroy Abraha in constructing churches in centers such as Najran, Zafar, and Aden, and ministering to a population that included pagans and a significant Jewish community.
The Disputation with Herban
The principal literary source associated with Gregory is the Disputation (Dialexis / Disputatio cum Herbano Judaeo), a Greek dialogue recounting a multi-day theological debate between the archbishop and a learned Jew named Herban (Ervan), set against a royal decree of baptism. In the narrative Gregory answers the elder's objections from the Old Testament scriptures.
Modern scholarship treats this Disputation as a literary composition: it was given its surviving form by an anonymous author in the late tenth century and incorporated into a Life drawn from earlier sources. Its dramatic episodes — including a vision and the conversion of the Jewish participants — belong to the hagiographic and traditional layer of the dossier rather than to documented history.
Repose and Commemoration
Gregory reposed on December 19, the date tradition assigns to his death (sometimes given as the year 552), and was buried in the cathedral of Zafar. He is commemorated on December 19 in the Synaxarion of Constantinople and the Orthodox calendar.
