How much Catholic, the Malabar Nasranis were from AD 1555 to AD 1599 is debatable. We had Mar Joseph Sulaqa and Mar Elias arrived from the Chaldean Patriarchate in AD 1555. (Even before him, one of the four Bishops arrived from Babylon with Joseph, the Indian in AD 1504, Mar Jacob Abuna had been certified as in conformity with the Roman Church by saint Francis Xavier in AD 1545.)
After Joseph Sulaqa, . Mar Abraham came from Non Catholic East Syriac Patriarcate in AD 1557 and was based at Angamali. Mar Abraham was arrested and deported but he joined the Chaldean Patriarchate and returned in AD 1568. So, in effect, both had received pallium from the Popes of Rome. In AD 1578, Mar Simon arrived from Non catholic East Syrian Patriarcate as Mar Abraham became Chaldean. He occupied his seat at Kaduthuruthy with a rival arch deacon Jacob while Mar Abraham and Arch deacon George of Christ based at Angamaly. In 1585, Mar Simon was arrested and deported. During the period 1578-1585, Saint Thomas Christian community appeared to be divided between Mar Abraham and Mar Simon with two rival arch Deacons.
Did they use the Pope’s name in the Qurbana ? It is documented that the Chaldean Patriarch’s name was replaced with the Pope’s name after the Synod of Diamper.
Do Eastern Catholic Churches remember the Pope’s name in their Qurbana or just the names of the Heads of their particular churches ? The story of Syro Malabar Church is different. SMC has been functioning as mere Roman Catholic dioceses with a different rite until only in 1996 when it was recognised as a Sui iuris Church with Major Arch Bishop as the Head of the Church. As SMC did not have a Father and head of the Church on its own, they remembered the Pope in the Qurbana. That may not be the case for other Eastern Catholic Churches.
After the Synod of Diamper, even though the Synod anathematised the Chaldean Patriarch (wrongly), the Saint Thomas Christians continued to remember the Patriarch’s name in the Qurbana along with the Pope’s name! Even the Syro Malabar Church continued to remember the Chaldean Patriarch’s name along with the Pope’s name in the Qurbana until recently in AD 1962 !
Realising that many of the decisions of the Synod of Diamper was unbearable to Saint Thomas’ Christians, Arch Bishop Roz convened a Synod at Angamali in 1603 to make amendments. In 1606, further relaxations to the Angamli Synod by making the Rozian statutes in AD 1606. Usage of the Patriarch’s name continued probably due to these relaxations.
During the time of Mar Jacob Abuna (1504- 1552), we were not in communion with the Roman Church, but Saint Francis Xavier has attested that Mar Jacob was in conformity with the Roman Church. It was during the time of Joseph Sulaqa(1555-1568) that Latin vestments were introduced among saint Thomas’ Christians and usage of unleavened bread for Eucharist. Mar Abraham (1568-1597) introduced Gregorian calendar as in Latin rite and banned marriage of Priests after ordination by his Synod of Angamali in 1583. But Mar Abraham resisted the decisions of the Goan Synod in 1585 which decided to translate the Latin liturgy into Syriac for saint Thomas Christians and to introduce celibacy for all priests.
So, the history of Saint Thomas’ Christians during AD 1555 period and after is very fluctuant. Pazhayacoor was separated from the Chaldean Patriarch forcefully and kept under the Roman Curia with arrangements to continue East Syriac liturgy and rites as modified by the missionaries. The laity and Priests continued the fight for restoration of the ancient Syro Chaldeac rite and even until 1900s, for restoration of connections to Chaldean Church. We can see Mar Thomas Rokos and Elias Melus arrived here on the request of the Catholic Syriac Nasranis. I think it was only after the native Prelates took over the leadership that they wanted to become independent of Chaldean Church and get rid of the Syriac traditions.