Baptism is one of the most significant obligatory sacraments in the Christian religion, via which one becomes fully Christian. It replicates the baptism of Christ by John the Baptist in the Jordan River, obeying the Lord’s command, “Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost.” (Matthew 28:19). According to the evangelists, the Holy Trinity was revealed during the Lord’s baptism, after which He began his salvatory work. Baptism is a milestone in the life of Christians. Τhey are absolved of previous sins, the old self dies and the person is reborn “through water [and blood] and the Holy Spirit”. The sacrament is rich in symbolism: the immersion of the body in water symbolizes the death of the Lord, while emergence symbolizes the resurrection. The tall candles represent the “light of the Spirit”, and the white garment worn by the newly baptized symbolizes the innocence and purity of the soul.

Before Christianity became predominant, those who embraced the new religion were baptized as adults in natural sources of water, such as lakes, rivers or the sea.  However, as early as the third century, separate rooms known as baptistries began to appear, and a special ritual was established for the celebration of the sacrament. Baptism was not separated from the Divine Liturgy performed during celebrations such as Christmas, Easter, the Epiphany and the Pentecost. Following a period of catechism, fasting and repentance, catechumens were led to the so called «photistirion», which had a permanent baptismal font. There they removed their old clothes and were immersed three times in baptismal water.  Then they put on new white garments and held a lighted candle in their hand. After baptism and chrismation (confirmation by anointment with holy chrism), they entered the church in procession and received communion for the first time. Separate baptistries ceased to be built from the mid Byzantine period onwards. Marble fonts have survived from the 10^th century onwards, as well as metal ones from mid-Byzantine times. These were placed in the narthex where the sacrament was performed. It was probably during the middle Byzantine period that baptism became a separate service.

As child mortality rates were far from low in the Byzantine period, infant baptism was established from early on and became widespread from around the 6^th onwards, ideally at the age of three. A Novella issued by Leo the Wise later ordered that infants should be baptized forty days after their birth, though the sacrament could be performed earlier if the infant was in danger of dying.

Because of the fear of sects, baptisms were performed by priests appointed by the bishop in the largest churches in each town, known as “catholic” (baptismal) churches, and not in country churches or private homes.  If the baby was in danger of dying, it could be “air baptized” by deacons, monks or even laymen.

The institution of sponsorship by a godfather or godmother appears in the Orthodox East as early as the second century. Sponsors were required to be orthodox and pious, and essentially became spiritual parent of the newly baptized, which meant that from a legal point of view they were granted the same full rights and obligations as the natural parents, while their children were regarded as brothers and sisters of the newly baptized. Godfathers would usually offer the baby gifts that reflected their social and economical status, which could be land or other some other property, but were usually limited to clothes and money.
During the ritual of baptism the child received its name. Although the godparent seems to have had the upper hand in deciding on a name, parents preferred to name their children after their grandparents or deceased relatives, as is still the custom. John Chrysostom urged parents to choose the names of saints, apostles or martyrs, or others related to celebrations (Epiphanius, Paschalios) or virtues (Elpida = “Hope”, Sophia – “Wisdom”).

Similar traditions were observed at royal christenings. No fixed day was set aside for such occasions, which could be held either shortly after birth or forty days thereafter, so that the mother could attend the sacrament. The baptism was performed by the Patriarch in the baptistry in Agia Sophia. The ceremony was followed by a procession from the church to the royal apartments in the palace, when alms were given to those thronging the streets to celebrate the event.