Since the sixteenth century it was propagated in the West that before the Synod of Diamper in 1599 the Liturgy of the St Thomas Christians was full of errors, heresies and blasphemies. How did these Christians celebrate the Eucharistic Liturgy before the arrival of the Western missionaries in the Sixteenth century? What was the shape of the Qurbana at the epoch of the Synod of Diamper? Which were the heretical doctrins and expressions of schism found in the pre-Diamper Eucharistic made by the Western missionaries, especially by Archbishop Menezes? What was the structure of the Qurbana after the Synod? This book is an attempt to answer such important questions, from historical, liturgical the theological perspectives, based on original sources and pertinent document.