Simplify the following text for a Grade 6 native English-speaking person.
Original: Biography , although popular throughout antiquity , was introduced as a branch of history by the works of Plutarch ( c. 46 â `` 127 ) and Suetonius ( c. 69 â `` after 130 ) who described the deeds and characters of ancient personalities , stressing their human side .
Simplified: Plutarch ( c. 46 - 127 ) and Suetonius ( c. 69-after 130 ) introduced biography as a branch of history .