The Schism of 1552 was an important event in the history of the Church of the East. It divided the church into two factions, of which one entered into communion with Rome becoming part of the Catholic Church at this time and the other remained independent until the 19th century. Although the Eliya line, which emerged as a result of this schism, did eventually enter into communion with Rome, various Spiritual Christian sects with their origins in the Church of the East emerged as a result of this schism. Ironically, the Shimon line whose entry into full communion with Rome caused this schism, in fact became independent again by the 17th century. The circumstances of the 1552 schism were controversial at the time and have been disputed ever since.
Around the middle of the fifteenth century the patriarch Shemʿon IV Basidi made the patriarchal succession hereditary, normally from uncle to nephew. This practice, which tended to result in a shortage of eligible heirs, eventually led to a schism in the Church of the East. The patriarch Shemʿon VII Ishoʿyahb (1539–58) caused great offence at the beginning of his reign by designating his twelve-year-old nephew Hnanishoʿ as his successor, presumably because no older relatives were available. Several years later, probably because Hnanishoʿ had died in the interim, he designated as successor his fifteen-year-old brother Eliya, the future patriarch Eliya VII (1558–91). Besides making these two provocative appointments, he was also accused by his opponents of permitting concubinage, selling clerical posts and living intemperately. By 1552 Shemʿon VII Ishoʿyahb had become so unpopular that his opponents rebelled against his authority. The rebels, principally from the Amid, Seert and Salmas districts, elected as patriarch a monk named Shimun VIII Yohannan Sulaqa, the leader of Rabban Hormizd Monastery near Alqosh. Unfortunately, no bishop of metropolitan rank was available to consecrate him, as canonically required. Franciscan missionaries were already at work among the Nestorians as well, and they legitimised their position by persuading Sulaqa’s supporters and getting him consecrated by Pope Julius III (1550–5).