Preparation
Before the Divine Liturgy begins, the priest and a deacon, if one is serving, begin by preparing the gifts of bread and wine for use in the service. This preparation is itself a considerable service. More than simply setting aside the bread and wine, a robust ritual has developed with elaborate symbolism. Though the main outline is similar for most Orthodox churches, there may be some differences based on which typicon a jurisdiction uses.
Five loaves of bread are used, reminiscent of the five loaves in the wilderness, from which the masses were fed. During the Prothesis, the priest cuts out a square called the Lamb from the main loaf of bread (prosphora). This will be consecrated during the Liturgy of the Faithful to become the holy body of Christ. He also removes small particles and places them on the diskos (or paten) in commemoration of the Theotokos, various saints, and the living and departed faithful. The remainder of the bread is blessed and distributed to parishioners and visitors after the service; this bread is called antidoron.
During the Prothesis, the priest also blesses wine and water, which are poured into the chalice. Warm water will be added to the chalice after the epiclesis.
Naturally, the gifts are censed several times during the Prothesis. The conclusion of the Prothesis leads directly into the beginning of the Divine Liturgy.