The tower at the center of the world
The point where the tower of Frederick II stands in Enna was sanctified and defined the gromatic center of the island of Trinacria.
According to some studies it is believed that the ancient astronomers designed the Sicilian road system, starting from the Tower of Frederick II, reproduced by the double-arm Patriarchal Cross, formed by the decumanus and the two hinges. On the South / West facade of the octagonal Tower of Enna the Sicilians in fact reproduced the fundamental scheme of the "Delimitatio Templus Caeleste" of Sicily, still clearly visible today, formed by eight vertical windows, the decumanus, and two rows of four horizontal windows. form the two hinges.
In the Sicilian road system, the meeting point between the decumantus and the first hinge was sacred and defined the gromatic center of the island of Trinacria, the Navel of Sicily and therefore, as believed by the ancients, the center of the Mediterranean and of the world. This point is where the tower stands.
Confirming this theory is the fact that the Tower is inserted within a system of turrets scattered throughout Sicily, perfectly aligned along the eight sides of the tower of Enna.
The tower of Federico II has other particular characteristics: on the first floor there are two large windows, one aligned with the summer solstice while the other aligned with the winter solstice.
It is also believed that the To rre presented on the ground floor a space reserved for surveying, i.e. that part of topography relating to the measurement, division and representation of land on large-scale maps and, on the first floor the study of geodesy, on the second floor the observation of celestial bodies . The second floor has not been preserved but the presence at the top of the structure of an opening formed by seven concentric circles that progressively narrower suggests, from the study of buildings with similar characteristics, that it had the purpose of capturing the sun's rays at the zenith of the equator during the phases of the equinox.
For all these characteristics it is believed that the octagonal tower of Frederick II can be considered the first astronomical-geodetic observatory in the Mediterranean area.