Father Ephraim discipled under Joseph the elder of Mt. Athos (celebrated locally by various churches as a saint, but not pronounced as such by the church at large, although his remains are incorrupt and fragrant), who was a great ascetic in the desert there at the time when in 1924 the patriarch of Constantinople, Gregory VII, introduced the New Calendar. All the monasteries on Mt. Athos resisted this, but one broke fellowship with the patriarch altogether, ceasing to commemorate him in their liturgy. This group came to be known as the zealots. This, as explained by Archbishop Gregory of the GOCA, was excessive, since Orthodoxy was united globally at that time and as represented by the pre-eminent Patriarchate of Moscow, rejected the New Calendar but did not break communion.
The Zealots approached father Joseph, who along with father Arsenius at that time probably already had a number of disciples in the desert of Mt. Athos. One of the disciples of father Joseph was the father Ephraim who later moved to Arizona, whom we are discussing. Father Joseph agreed to this separation, but through prayer learned that this was a mistake and he and the monks with him recanted of it.
Father Ephraim remained obedient to Father Joseph until his death in 1959, but soon after this, in 1965, the great apostasy of Orthodoxy occurred. It was then that Patriarch Athanogoras of Constantinople brought the Orthodox into the ecumenist movement. Although the big monasteries on Mt. Athos went along with this, father Arsenius and the other monks around him, including father Ephraim, did over this issue finally break communion. This is the action they felt was required to remain true to the legacy and tradition and the spirit of father Joseph. They took the stand that World Orthodoxy had left the Church.
But in 1973 father Ephraim was offered the big monastery of Philotheo. There is no doubt that this would have required commemorating the patriarch, Athanogoras, as this was the position of all the big monasteries on Athos. Ephraim was thus tempted and re-joined World Orthodoxy, becoming Abbot of the Philotheo monastery on Mt. Athos. He revitalized that and other monasteries on the peninsula. The problem was that now World Orthodoxy was in the heresy of ecumenism.
In the early 1980s he came to America hoping to start monasteries there. However the Greek diocese, which he was under, was not interested in this. Seeing this, Ephraim broke fellowship with World Orthodoxy again and joined the Russian Church Abroad (ROCOR) which at that time was not in fellowship with it. This seems to have been a decision more of convenience than of conviction.
The then current Greek patriarch, Demetrius, was embarrassed by this alliance and soon invited Ephraim to Constantinople where they threatened him and he remained in Greece for a time before returning to America back under the auspices of the Greek archdiocese to build the monasteries that they had formerly resisted.
Father Ephraim is now under Patriarch Bartholomew, who says that we all worship the same God, whether we call him Allah, Yahweh, or Jesus Christ. Today World Orthodox bishops go to Rome and con-celebrate with the Pope. They say we are two lungs of the same body. They make videos saying that Christianity is divided into two parts: those in the West led by the Pope, and those in the East led by the Patriarch of Constantinople. Father Ephraim and those with him don’t like it, and they protest. But in the view of Archbishop Gregory of GOCA, and presumably in the view of father Arsenius and father Joseph the only proper protest to this heretical behavior is to break fellowship with them.
The above are my notes from a video that hopefully you can find at this link at Orthodox Videos.