Simplify the following text for a Grade 9 native English-speaking person.
Original: Until 1384 , Arezzo was an independent city-state , generally Ghibelline in tendency , thus opposing Guelph Florence .
Simplified: The commune of Arezzo threw off the control of its bishop in 1098 and was an independent city-state until 1384 . Generally Ghibelline in tendency , it opposed Guelph Florence .