The change of church music to instrumental is often tied to the Papacy. There are several works we can cite to discuss the issue.
The Catholic .Encyclopedia .(1913 edition) states that "according to Plating (`De vitis Pontificum', Cologne, 1593), Pope' Vitalian (657-72) introduced the organ into the church service. This, however, is very doubtful. At all events, a strong objection to the organ in church service remained pretty general down to the twelfth century, which may be accounted for partly by the imperfection of tone in organs of that time. But from the twelfth century on, the organ became the privileged church instrument . . ." (Vol. XI, pp. 300-301).
http://truthmagazine.com/archives/volume24/TM024135.html
Yet, it seems the first instruments in post AD 70 religious music were introduced, not by Christians, but by Islamists and Jews during the Muslim insurrection into Europe 600-800 A.D. The Southern Byzantine empire was taken by Islam along with much of southern Europe. Originally Muslims rejected instruments, but later adopted them in a reserved fashion. Jews did not have a big foot print after AD 70 but during the founding of Constantinople and later the Islamic conquests were given a reprieve, being freed from Christian control so that they could re-introduce their religious ideas.
The Jewish Talmud highlighted instruments used in the temple but it wasn't until Byzantium was divided into a Muslim Caliphate that they made a come back. Keep in mind that Constantinople itself was not founded until 330 AD. It was in this period archeological finds found older types of organs, not those associated with Bellows. Constantinople was associated with the emperor and thus the musical advancements. Also, the Byzantine Empire from 220 on granted Jews some religious freedom and legal status. Even though segregated,the Jews could openly practice and teach their history.
We do know that windpipes or bagpipes were used in the middleeast in the first century.
The evidence for pre-Roman era bagpipes is still uncertain but several textual and visual clues have been suggested. The Oxford History of Music says that a sculpture of bagpipes has been found on a Hittite slab at Euyuk in the Middle East, dated to 1000 BC. Several authors identify the ancient Greek askaulos (ἀσκός askos – wine-skin, αὐλός aulos – reed pipe) with the bagpipe.[2] In the 2nd century AD, Suetonius described the Roman emperor Nero as a player of the tibia utricularis.[3] Dio Chrysostom wrote in the 1st century of a contemporary sovereign (possibly Nero) who could play a pipe (tibia, Roman reedpipes similar to Greek and Etruscan instruments) with his mouth as well as by tucking a bladder beneath his armpit.[4]
https://en.wikipedia.org/wiki/Bagpipes
The bellows organ in theory was simply a bigger bagpipe.
The organ used in churches was not invented until the 6th or7th century. Before its time a water organ was invented but not used in churches. The Bellows organ was invented but not practiced until improvements were made. The first use of the bellows organ was a novelty, since it was recently invented. https://en.wikipedia.org/wiki/Pipe_organ
The bellows were claimed to be invented by Muslims and most windpipes employed were in the middleast, Muslim Africa, and Muslim Spain.. There seems to be proof of a bellows organ in the 2nd century AD, so we cannot honor the boast that Muslims invented the organ, but they were central in the development and use of smaller versions. The organ had been lost in the west until the 8th century, so that any production of such music was limited to the east, or the Byzantine empire which came to be ruled by Greco Roman remnants and Islamists.
Performance art and music theory came together in the royal courts of Al-Andalus throughout the period of Muslim rule. Ziryab whose real name was Abul-Hasan Alí Ibn Nafí, born in Iraq in 789 CE of North African heritage was a musician who represented the courtly arts and cultivated society. Al-Hakam, father of Abd-Al-Rahman II, invited him to court at Córdoba. Ziryab had studied music under a famous teacher in Baghdad, and he brought knowledge of music performance and knowledge to the Muslim lands of the west. He established a music conservatory in Córdoba that trained young musicians, spreading his influence to other courts.
http://www.islamicspain.tv/Arts-and-Science/The-Culture-of-Al-Andalus/Music.htm
Islam had formally made rulings that instruments were allowable in worship as long as they met certain requirements and followed other rules of Islam. Though not used in Christianity, it seems the rulings gave Islam a political tool for converting those who had used them in their Roman religions. Christians had made judgments much earlier that instruments were allowed in feasts but no mention of worship. Thus Islam went one step further.
Since the regions of southern Europe came under Islamic law it is certain Christians had a legal right to forbid instruments, and we can conclude Islam was instrumental in providing the legal framework for change. Churches did not have the right to openly say Islamic judgments were wrong.
Islam had taken over parts of southern Europe during this period and many Churches were forced to leave the region or concede honor to Muslim governors. The governors forced Christians to do certain things or be liquidated entirely. Most fled North. Christian churches and governors were forced to appease Muslim governors in many respects. Wars were fought often but cultural war was daily fought. All cultures battled to appeal to other groups, especially those coming out of Roman and Greek religions.
The organ at the time was solely used secularly as Christians did not use instruments except in feasts and in emperors dwellings. Islam started out as a chanting religion based in the religions of the area. The Babylonian Talmud was written but not completed until the 5th century. It is the Talmud that was most responsible for the organ in religious music in religious music..
It was during this period that the first known organ that came to be associated with Christian music was given as a gift from an emperor in Byzantium to a Christian king named Pepin. Pepin was newly converted to Catholicism, but no one in the west used instruments, and this organ was not given for Christian worship, but to compliment Pepin's newly built secular Cathedra (Chair). Most works cite simply Byzantium as the source, at the time Byzantium had both Christian and Muslim presence. It seems the gift came from a caliph, and thus Muslim. Catholics associate the organ with the governor of Constantinople, but he likely got it from Muslims, at least the concept and invention. Organs of lesser quality had been used around Constantinople for some time.
Music of this type was lost in the West, and the gift of the organ was meant to be a sharing of general culture.
The real source of introduction, when religious questions were raised, came from the Jewish Talmud which confused a tool known as a magreph with an organ as devised by Muslims. The Jews openly claimed the magrepha for music, but it was a signaling instrument, dropped by servants in the temple to call the unclean to sacrifice. The magrepha was not used in music.
https://jhva.wordpress.com/2011/01/19/the-big-bang-from-jerusalem/
Thus, the magreph became confused with an organ, and the stage was set to enjoin the organ to worship. Today it is associated with instruments concerning organs.
2nd century - the Magrepha, ancient Hebrew organ of ten pipes played by a keyboard[17][18][19]
9th century - the automatic flute player (and possibly automatic hydropowered organ), a mechanical organ by the Banū Mūsā brothers
This description is from Wikipedia and the confusion exists to this day.
The Arab–Byzantine wars were a series of wars between the mostly Arab Muslims and the East Roman or Byzantine Empire between the 7th and 11th centuries AD, started during the initial Muslim conquests under the expansionist Rashidun and Umayyad caliphs in the 7th century and continued by their successors until the mid-11th century.
These wars made way for Jewish renewal in the face of Christianity, and what I refer to as the rise of Anti-Christ powers in Judaism and Islam. Both denied his deity and Sonship. It wasn't until the 12th century that the organ became prominent in churches. This was through the exchange of culture, a general introduction of music in churches to honor Jewish culture.
The emergence of Muslim Arabs from Arabia in the 630s resulted in the rapid loss of Byzantium's southern provinces (Syria and Egypt) to the Muslim Caliphate. Over the next fifty years, under the aggressive Umayyad caliphs, the Muslims would launch repeated raids into still-Byzantine Asia Minor, twice threaten the Byzantine capital, Constantinople with conquest, and outright conquer the Byzantine Exarchate of Africa. The situation did not stabilize until after the failure of the Second Arab Siege of Constantinople in 718, when the Taurus Mountains on the eastern rim of Asia Minor became established as the mutual, heavily fortified and largely depopulated frontier. Under the Abbasid Empire, relations became more normal, with embassies exchanged and even periods of truce, but conflict remained the norm, with almost annual raids and counter-raids, sponsored either by the Abbasid government or by local rulers, well into the 10th century. https://en.wikipedia.org/wiki/Arab%E2%80%93Byzantine_wars
It was during these wars that the gift of an organ was passed from Byzantium to Pepin and Charlamagne. It could be the organ was not for church music, since Charlamagne's throne was located by the Aechen Cathedral. It, the Cathedra, was used for both secular and church duties. The organ as a gift was for his secular throne and not necessarily religious.
It came to be associated with Christian religion because of its proximity to the Cathedral. Music could be played daily much like bells at a church today. It was for general novelty but not worship.
Initially it became referenced to music through the Talmud deception. As the actual use of the organ was forgotten by future generations.
A later organ was built for the Cathedral in 900-1000 AD.
https://en.wikipedia.org/wiki/Aachen_Cathedral
He noted accounts of an organ being sent from Byzantium to Pippin [Pippin the Short, ruler of the Franks (741-768)] in 757, and another to Charlemagne [Charles the Great (742-814), first emperor of the “Holy Roman Empire”] in 812. The reactions of curiosity and awe concerning these organs indicated “they did not exist in Gaul during the centuries immediately preceding their arrival from the East” (p. 276).
They seem to be gifts to kings, and not the church per se. As the Cathedra of Rome began to be associated with the secular ruler and papacy, it is likely they were not first employed in church music.
Roman Catholics normally cite a tradition from300 years later t as authority it was used for church music, but a 10th century work proves little. It only says Charlamagne wanted to borrow two singers from Rome, which could be accapella singers. It proves very little. Plus, since the Organ was recently invented it would have no tradition before the Romans incorporated it.
It can be seen as a gift from one king and one civilization to another, but was eventually used as a means to divide the Church, forcing some to break the history of church worship and music.
Jason Cristiano Ramon
Islam and Byzantium
http://peopleof.oureverydaylife.com/islam-byzantium-4037.html
While the western half of the Roman Empire disintegrated during the fifth century A.D., the eastern part of the Roman Empire -- commonly referred to as Byzantium or the Byzantine Empire -- flourished for another 10 centuries. As Byzantium faced ongoing territorial clashes with Islamic caliphates, a rich cultural cross-fertilization took place between Muslims and Orthodox Christians, as Islamic culture integrated Judeo-Christian forms of worship and preserved ancient Greek texts vis-a-vis Arabic translations.
This era brought Islam closer to orthodoxy, but it also brought the church closer to Judaism. It developed three anti-Christian forces that would battle each other and battle the church.