Prosphoro - which means "an offering" - is an ancient tradition in the Orthodox Church.
For the entire history of the Church, Christians have baked and brought bread to the for the Sacred Meal, Holy Communion. Prosphoro is specially-made bread, impressed with a seal, that is cut by the priest in a service called the "Proskomide" during which he prays for the living and the dead. The center portion, the Amno or Lamb, is that piece which will be consecrated during the Divine Liturgy. This is the bread that becomes the Body of Christ.