The Trinity is the main dogma of Christian Religion. This doctrine states that God has three hypostases(in Greek)as God the Father, God the Son(Jesus Christ
) and God the Holy Spirit. This concept of Trinity has been introduced by Jesus Christ Himself to first apostles: "Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you"(Matthew 28:19-20).
The common Orthodox representation of the Trinity is as the "Old Testament Trinity" of the three angels visiting Abraham.