What was the feud that Romeo and Juliet based on?

The feud between the Montagues and Capulets is based on a real-life feud between two noble families in Verona, Italy, during the 13th century. The Montagues and Capulets were two of the most powerful families in the city, and their rivalry was fueled by a long-standing dispute over land and power. The feud between the Montagues and Capulets eventually led to the deaths of Romeo and Juliet, two young lovers from opposite sides of the family divide.