What is "medieval latin"

Medieval Latin was the form of Latin used in the Middle Ages, primarily as a medium of scholarly exchange and as the liturgical language of Chalcedonian Christianity and the Roman Catholic Church, but also as a language of science, literature, law, and administration. Despite the clerical origin of many of its authors, medieval Latin should not be confused with Ecclesiastical Latin. There is no real consensus on the exact boundary where Late Latin ends and medieval Latin begins. Some scholarly surveys begin with the rise of early Ecclesiastical Latin in the middle of the 4th century, others around 500, and still others with the replacement of written Late Latin by written Romance languages starting around the year 900.