Χριστέ, ἐλέησον...Kyrie Eleison

​In the Eastern Roman Empire the common language of the people was Greek. Even in Rome where the language of the governing classes was Latin the mass was however celebrated in Greek until the third century. From the third century onward the Mass was in Latin in the West. The change in language was done so that the people could understand what was being said in their own language. In the fifth century the Kyrie Eleison became part of the liturgy in the West. It was an adoption of Greek customs from the eastern Church. The Kyrie Eleison is a Greek prayer which is a repeated asking God for mercy. Kyrie Elsison is a transliteration into Latin letters of the Greek phrase  Χριστέ, ἐλέησον which means “Lord, have mercy.”