Simplify the following text for a Grade 9 native English-speaking person.
Original: Some scholarly surveys begin with the rise of early Ecclesiastical Latin in the middle of the 4th century , others around the year 500 AD , and still others with the replacement of written Late Latin by written Romance languages starting around the year 900 ( see under Late Latin ) .
Simplified: Some scholars have their surveys of it begin with the rise of early Christian Latin in the middle of the 4th century , others around the year 500 .