Located in Puglia, Castel del Monte (Italian for "Castle of the Mountain") was built in the 13th century by Emperor Frederick II, who had inherited the lands from his mother Constance of Sicily. Frederick was responsible for the construction of many castles in Puglia, but Castel del Monte's geometric design was unique.

The emperor imbued it with symbolic significance, as reflected in the location, the mathematical and astronomical precision of the layout (studied so as to create symmetries of light during the winter solstice and summer equinox) and the perfectly regular shape (which uses eight as a guiding number).