Originally known as the Palazzo dei Priori and later as the Palazzo della Signoria and Palazzo Ducale, the 13th-century Palazzo Vecchio was built to house the Priori, the leaders of the guilds, following the establishment of the popular government in 1283. The new palace was an architectural statement of the new political order that followed the resolution of the fierce fighting between the Guelph and Ghibelline factions in the city. The Palazzo Vecchio (still the town hall of Florence) set the pattern for Central Italian civic architecture during the 14th century. The palace subsequently underwent many changes, both internally and externally. In the 15th century, when it was known as the Palazzo della Signoria, Michelozzo was charged with shoring up the internal courtyard and fortifying the tower, both of which were in danger of imminent collapse; the present courtyard is very different from the 13th-century original. This courtyard was decorated by Vasari, ca. 1572.