"Palazzo Pretorio", the old town hall, was built at the end of the 13th century in red bricks. Sections in white brick were added later. In the 16th century an outside staircase and a clock were added. Also notable is the "Palazzo Datini", the home of the merchant Francesco Datini built from 1383. It has decorations by Florentine artists like Agnolo Gaddi and Niccolò Gerini. In 1409, it housed Pope Alexander V and Louis of Anjou. The "Palazzo degli Alberti" (12th century) is home to an artgallery with works by Filippo Lippi ("Prato Madonna"), Giovanni Bellini ("Crucifix with Jew Cemetery") and Caravaggio ("The Crowning with Thorns").