Simplify the following text for a Grade 10 native English-speaking person.
Original: Around 1100 CE it was the center of struggle between the free communes of Milan and Como : in the 14th century it was definitively acquired by the Visconti , Dukes of Milan .
Simplified: Around 1100 it was the center of struggle between the free communes of Milan and Como : in the 14th century it was acquired by the Visconti , Dukes of Milan .