Assimilation to Greek Orthodox Christianity from the Armenian Apostolic Church was a common practice among Anatolian Armenian populations during the Middle Ages, when mixed Armenian-Greek military families ruled the Byzantine Empire from Constantinople and appointed their family members to the role of Patriarch of the empire's Eastern Orthodox church.
Many of the greatest Byzantine scholars, generals, clerics and emperors were of Armenian heritage and adopted the Greek Orthodox faith out of formal necessity, (as in the case of emperors and Patriarchs who had to be of the Greek Orthodox faith), or out of cosmopolitanism.
Precious objects of culture belonging to this small community are displayed today in Athens at the Benaki Museum.
In the region of Agn by the 20th century Hayhurums were essentially concentrated in 5 villages: Vag, Zorak, Musaga, Sirzu, Hogus.
[1] In the medieval era there were more Hayhurum villages throughout the Kemaliye, Dersim, Erzincan region but due to Islamization, depopulation from the Perso-Ottoman wars, Turkification, and migration to western Anatolia, their numbers shrank.