Oriental Orthodoxy is the second largest Christian denomination in Iraq after the collective Eastern Catholic Churches.
[1][2][3] The early history of Oriental Orthodoxy on the territory of modern-day Iraq was marked by constant Byzantine-Sasanian wars during the period between 5th and 7th century.
In that period, major part of the Mesopotamia region was ruled by the Sassanian Empire (Persia).
Since official Persian religion was Zoroastrianism, all Christian communities in the region were under constant pressure, and suffered occasional persecutions.
In order to consolidate ecclesiastical structure of Oriental Orthodox churches within the Sassanian Empire, the Patriarchate decided to appoint theologian Marutha of Tikrit as metropolitan over all Oriental Orthodox dioceses in the Empire (629), granting him the title of maphrian.