Castel del Monte has an exceptional universal value for the perfection of its forms, the harmony and the fusion of cultural elements from Northern Europe, the Muslim world and classical antiquity.

It is a unique masterpiece of medieval architecture, reflecting the humanism of its founder: Frederick II of Swabia.

With this reason, in 1996, the UNESCO World Heritage Committee gathered in Merida (Mexico), included in the World Heritage List the castle, made by Frederick II of Swabia around 1240.

The only document of the Federician era concerning the monument is a mandate of 29 January 1240, with which the king, from Gubbio, ordered Riccardo da Montefuscolo, Giustiziere di Capitanata, to buy lime, stones and anything else needed "...pro castro quod apud Sanctam Mariam de Monte fieri volumus".

In this document the Latin term actractum was used, susceptible to various interpretations: floor, ground levelling, roofing slabs, up to a more generic meaning of building material.