Simplify the following text for a Grade 13 native English-speaking person.
Original: Arezzo in 1384 was under Florentine dominationDuring this period Piero della Francesca worked in the church of San Francesco di Arezzo producing the splendid frescoes .
Simplified: During this period Piero della Francesca worked in the church of San Francesco di Arezzo producing the splendid frescoes , recently restored , which are Arezzo 's most famous works .