The Orthodox Church is supposedly the original church founded by the Lord Jesus Christ Himself and His early apostles. The Church is said to begin at the day of Pentecost with the 120 in the upper room in Jerusalem as recorded in Acts of the Apostles chapters 1 and 2 and at the advent of the Holy Spirit in A.D. 33. It is known and referred to by the West as the Eastern Orthodox Church or the Greek Orthodox Church.
The Orthodox Church holds that their bishops are an unbroken succession of the very apostles of the Lord themselves, and in that sense receives their consecrations from the Lord Jesus Christ Himself. In that regard, the belief and practices held by the church is what was passed down by the Lord Christ Himself to the original apostles, no more, no less.