The old town was built over three hills (St. Trifone or St. Rocco Hill; Episcopate's Hill; St. Giovanni Hill) in Byzanthine times. There are doubts on the origin of the name, some say it derived from two Byzanthine generals, Katà and Zaro, while another theory is that Zaro was the original name of the river, so that katà Zaro would mean beyound the river.
It was the first place in Italy to introduce the breeding of the silkworm in the 11th century. The peasants of the countryside around the city produced the raw silk, which was then woven in the silk workshops of Catanzaro. A large part of the population was involved in this business, and the silk of Catanzaro supplied almost all of Europe. The silk was sold in a large market fair in the port of Reggio Calabria, to Spanish, Venetians, Genovese and Dutch merchants.
A devastating earthquake in 1783 wiped away churches, palaces and a large part of the population. And a second in 1832 completed the destruction of most ancient historical buildings.