…there are many passing references to music scattered throughout the writings of the Fathers. Most of the passages deal with psalmody and vocal music, but a few are concerned with musical instruments. The authors of these passages were almost unanimous in rejecting the use of musical instruments. The Fathers brought three basic arguments to bear on the question of instruments: (1) instruments and other “ceremonies” were characteristic of the “infancy” of the church (i.e., the Jewish Dispensation), while the church was now in its maturity (the Christian Dispensation); thus, (2) the numerous references to instruments and instrumental music in the Old Testament should be interpreted symbolically; and (3) instruments were associated with immoral practices, even as some pagan writers had noted. …[T]he Fathers do not seem to have been writing in reaction to contemporary Christian practice. That is, they were not trying to correct abuses that had crept into the Christian church, for there is very little evidence that instruments had ever formed a part of Christian worship during its practice in the early centuries…..
The vehement and unanimous objections of the Church Fathers to musical instruments apparently succeed in suppressing their use in Christian worship for many centuries. Indeed…at least one instrument, the Greek hydraulic organ, appears to have been largely forgotten in the West…..
The demise of the organ as a common instrument in the West was so complete that when one arrived as a gift at the court of the Franks in 757 it was regarded as a great novelty.
—David W. Music, Instruments in Church: A Collection of Source Documents, vol. 7, Studies in Liturgical Musicology (Lanham and London: The Scarecrow Press Inc, 1998), 27, 43.