The Holy Qurbana, refers to the Eucharistic liturgy as celebrated in Syriac Christianity and the liturgical books containing the rubrics for its celebration. Churches that celebrate this liturgy include various descendants of the Church of the East. East Syriac Christianity consists of an Edessan liturgical rite called the East Syriac Rite. The major anaphora of the East Syriac tradition is the Holy Qurbana of Saints Addai and Mari; Addai being a disciple of Thomas the Apostle and Mari being Addai's disciple. These churches are primarily based in the Middle East and India, with diasporic communities settled in the western world.