The True Orthodox Christian movement appeared in Greece in 1924, in connection with the introduction of the New Calendar, and thereupon similar groups appeared in Romania and other countries throughout the world. The largest True Orthodox Christian movement, however, also known as the Catacomb Church, appeared in Russia in 1927, following the Declaration of Metropolitan Sergius, which submitted the Church to the God-hating Bolshevik authority. ...
In his prophetic sermons, St. John of Kronstadt said that the Antichrist could not appear among us because of the autocratic imperial authority, which restrained the shameful and mindless teachings of the godless. As he explained the words of the Apostle Paul, For the mystery of iniquity is already at work: only that he who now restraineth doth restrain, until he be taken out of the way. 8 And then that wicked one shall be revealed: whom the Lord Jesus shall slay with the spirit of his mouth and shall destroy with the manifestation of his coming. (II Thessalonians 2: 7-8). St. John of Kronstadt explains this by saying that the Antichrist will not appear on earth as long as the autonomous imperial authority existed. "He who now restraineth" is, in his deep conviction, the Russian Orthodox Tsar-Autocrat. "The Lord preserves the well-being of the earthly kingdom and especially the well-being of His Holy Church, and will not allow the teachings of the godless, heretics, and schismatics to overwhelm it." This "overwhelming" was precisely what did occur in the decade after the murder of the Holy Royal Martyrs. Apostasy began to spread quickly, freely, and openly. Orthodoxy was engulfed by the waves of Renovationism, the New Calendar Schism, Sergianism, Modernism, and the desire to "reform" the Church in the image of Protestantism. In the end appeared Ecumenism, which Fr. Justin Popovich correctly called the "pan-heresy," because it unites in itself all the unorthodox teachings in the world. ...
In Greece after the New Calendar schism, the faithful were left with only a priesthood at the presbyteral level, with no bishops, because at that point all of the hierarchs had accepted the calendar change. In 1935, however, eleven years after the calendar change, hierarchs consecrated before the 1924 schism returned to the True Church and undertook the archpastoral care of the True Orthodox of Greece. After the repose of Metropolitan Chrysostomos of Florina, in 1955, they were again left without hierarchs, but in 1961 bishops of the Russian Church Abroad began the process of consecrating bishops for the True Orthodox Church of Greece, consecrations which were later regularized by the decree of the Russian Church Abroad in 1969, under St. Metropolitan Philaret.
In Serbia, the faithful who separated from the ecumenist Belgrade Patriarchate in the 1990's had no bishops or priests, only monastics and laity. The hierarchs of the Greek GOC ordained priests for Serbia, and the Serbian True Orthodox flock came under the temporary administrative care of the Greek GOC