The first development at Scicli was around the Castello dei tre cantoni at the top of San Matteo hill that overlooks the town. The Castello dei tre Cantoni is actually composed of two separate fortifications, the Castelluccio higher up and the Castellaccio at a lower level.
This was a defensive structure that, over the centuries, was enlarged and used first by the Arabs, then by the Normans and then later as a military outpost of the County of Modica. The current castle is dated to the 13th century although studies date its origins to the first half of the 12th century.
The Castle has a triangular tower, while to the north-east stands a large wall terminating in a quadrangular tower. The reason for having an unusual triangular tower is unknown, but thought to be symbolic (possibly related to the three points of Sicily itself) rather than a military function.
References:The Amphitheatre of the Three Gauls was part of the federal sanctuary of the three Gauls dedicated to the cult of Rome and Augustus celebrated by the 60 Gallic tribes when they gathered at Lugdunum (Lyon). The amphitheatre was built at the foot of the La Croix-Rousse hill at what was then the confluence of the Rhône and Saône.
Excavations have revealed a basement of three elliptical walls linked by cross-walls and a channel surrounding the oval central arena. The arena was slightly sloped, with the building"s south part supported by a now-vanished vault. The arena"s dimensions are 67,6m by 42m. This phase of the amphitheatre housed games which accompanied the imperial cult, with its low capacity (1,800 seats) being enough for delegations from the 60 Gallic tribes.
The amphitheatre was expanded at the start of the 2nd century. Two galleries were added around the old amphitheatre, raising its width from 25 metres to 105 metres and its capacity to about 20,000 seats. In so doing it made it a building open to the whole population of Lugdunum and its environs.