Jesus grew up hearing men sing in the temple and synagogue. All Jewish boys grew up hearing this singing. Though it cannot be said with certainty, my guess is that had you been the upper room host that night, waiting on Jesus and his group to clear the room so you could take out the garbage and put the red and blue hymnals back where they belong, you would be hearing a strong Eastern flavor of singing.
Singing in the church during the one or two generations after Jesus’s resurrection would have retained a strong Jewish flavor. Gradually, as the disciples spread into more distant parts of the Roman Empire, and the church was opened to gentiles, and as the development of Western music and musical instruments advanced, the singing of hymns began to take on slightly different forms, though still in the form of chant.
It was Pope St. Damascus (366-384) who convoked at Rome a council to which he invited many of the oriental bishops of the Eastern Orthodox Church at Constantinople and the other important sees of that area.