This is Life!: Revolutions Around the Cruciform Axis

Our Fathers Among the Saints, the Three Hierarchs Basil, Gregory and John

Troparion of the Three Great Hierarchs Tone 1
Let all who love their words come together and honour with hymns/ the three luminaries of the light-creating Trinity:/ Basil the Great, Gregory the Theologian,/ and renowned John of golden speech,/ who have enlightened the world with the rays of their divine doctrines,/ and are mellifluous rivers of wisdom/ who have watered all creation with streams of divine knowledge;/ they ever intercede with the Trinity for us.

Kontakion of the Three Great Hierarchs Tone 2
Thou hast taken the sacred and divinely inspired heralds,/ the crown of Thy teachers, O Lord,/ for the enjoyment of Thy blessings and for repose./ For Thou hast accepted their sufferings and labours above every burnt offering,/ O Thou Who alone dost glorify Thy Saints.

From the OCA website:

During the eleventh century, disputes raged in Constantinople about which of the three hierarchs was the greatest. Some preferred St Basil (January 1), others honored St Gregory the Theologian (January 25), while a third group exalted St John Chrysostom (November 13).

Dissension among Christians increased. Some called themselves Basilians, others referred to themselves as Gregorians, and others as Johnites.

By the will of God, the three hierarchs appeared to St John the Bishop of Euchaita (June 14) in the year 1084, and said that they were equal before God. "There are no divisions among us, and no opposition to one another."

They ordered that the disputes should stop, and that their common commemoration should be celebrated on a single day. Bishop John chose January 30 for their joint Feast, thus ending the controversy and restoring peace.