Different reasons are proposed to explain why from the seventh century, beginning in Gaul, priests in the West came to pray the Roman Canon inaudibly for all but themselves. According to Elizabeth Harrington, "by the late 800s it came to be considered too holy to be heard by the people and was prayed in a low voice". The spread of the practice from East Syria, where it had originated, to the Greek-speaking Byzantine Empire is witnessed to by Emperor Justinian's legislation against it in 565, a time when it was still unknown in Rome. Uwe Michael Lang proposes another factor for its adoption in the West: the impossibility for the priest of making his voice heard in the vast Roman basilicas and other large churches.