The Mystery of Chrismation is usually performed immediately after baptism as an integral part of the Baptismal service. This is the confirmation or seal of union with the Holy Church. The prayer of Chrismation says, “bestow on him (her) the seal of the gift of Your holy, omnipotent and worshipful Spirit and communion in the Holy Body and most Precious Blood of Your Christ. Keep him (her) in Your sanctification; confirm him (her) in the Orthodox Faith; deliver him (her) from the Evil One and all his devices. And guard his (her) soul, through redeeming fear of You, in purity and up rightness, so that pleasing You in every word and deed, he (she) May become a child and heir of Your heavenly kingdom.”
Chrismation was originally done by the Apostles by the laying on of hands. As the number of Christians grew and spread to various lands, this act was replaced by the use of a special myrrh that was received from the hands of the Apostles.
Now He who establishes us with you in Christ and has anointed us is God, who also has sealed us and given us the Spirit in our hearts as a guarantee. (2 Cor 1:21-22)
The word Chrisma has a close relation to the word Christian as Christians were often called the anointed ones.
In the West, Chrismation was separated from baptism in the 13th century. In the Roman church it is given to those who have become “the age of discretion” usually about seven years of age.