Simplify the following text for a Grade 8 native English-speaking person.
Original: In the 13th century it was acquired again by the Aldobrandeschi , but later it passed to Pisa and then the Appiani of Piombino .
Simplified: In the 13th century it was bought again by the Aldobrandeschi , but later it passed to Pisa and then the Appiani of Piombino .