The city's name derives from the Arabic 'qal'at-al-jarar' ('Castle of jars') – a name that attests to the antiquity of the pottery works which are still thriving. It has been inhabited since prehistoric times, as shown by the presence of two necropoleis dating from the second millennium BCE and by numerous other archaeological finds. It was later inhabited by the Sicels pre-Roman population.
The Arabs built a castle here that in 1030 was attacked by Ligurian troops under the Byzantine general George Maniakes, who have left traces of Ligurian language in the current dialect. The city flourished under the Norman and Hohenstaufen domination, becoming a renowned center for production of ceramics.
Caltagirone was almost completely destroyed by the earthquake of 1693. Many public and private buildings have then been reconstructed in earthquake Baroque style. Primarily for this reason the city has been included, together with the surrounding territory, in an area protected by the UNESCO World Heritage program.References:
The Petersberg Citadel is one of the largest extant early-modern citadels in Europe and covers the whole north-western part of the Erfurt city centre. It was built after 1665 on Petersberg hill and was in military use until 1963. It dates from a time when Erfurt was ruled by the Electors of Mainz and is a unique example of the European style of fortress construction. Beneath the citadel is an underground maze of passageways that can be visited on guided tours organised by Erfurt Tourist Office.
The citadel was originally built on the site of a medieval Benedictine Monastery and the earliest parts of the complex date from the 12th century. Erfurt has also been ruled by Sweden, Prussia, Napoleon, the German Empire, the Nazis, and post-World War II Soviet occupying forces, and it was part of the German Democratic Republic (East Germany). All of these regimes used Petersberg Citadel and had an influence on its development. The baroque fortress was in military use until 1963. Since German reunification in 1990, the citadel has undergone significant restoration and it is now open to the public as a historic site.