The excavations of the 13nth Ephorate of Pre-historic and Classic Antiquities under the direction of the archeologist George Rethemiotakis brought to light traces of settlements going back as far as the Neolithic period.

The most ancient residents of Kastelli seemed to have lived in the area of Kastelli's current central square called Meidani. The excavations in that area have revealed finds from the Neolithic period as well as architectural remains and objects dating as back as the Proto- Minoan (3500- 2110 B.C.) and Middle-Minoan period (2100-1800 B.C.), when it was destroyed by fire around 1700 B.C.

With the beginning of the New-Palatial period, the settlement was transported to the eastern region of what we now call Kastelli. Part of this settlement has been located in the Kabitaki area, in a place known as Petras (Stone) along with a temple with a definite rural-shepherd character.

This The New-Palatial settlement had been developed around a central two-storied building of monumental dimensions, the architectural relic of which is also visible today in the square of Agios Georgios (Saint George). The central building, which has been reconstructed at least once, had eight rooms and was used until the years of 1500-1460 BC, having been later destroyed.

One of these rooms seemed to have been used as a sacristy. Another room with many windows, located in the interior of the building was used for worship and various religious activities. A wide street that has been excavated alongside the south of the building connected the two stores building with the eastern part of the settlement. The excavation of a platform alongside the road in the south and southeast of the central building shows according Mr. Rethemiotakis the ceremonial character of the road and reminds the design of Minoan palaces, were that space was used for various social activities. The intervisibility of the south side of the building with the hill called the Kefalas peak sanctuary, in Liliano village, strengthens the above interpretation

Between 1460-1050 B.C. the settlement appears to have been under the influence of Knossos, and new modern residences contemporary to the ones that were found in the plot of the parish of Kastelli were built around it.

The remnants of the central building have been maintained up to the Hellenistic years, perhaps because of respect or maybe superstition of the newer residents, avoiding new construction in that area.

The Hellenistic settlement of Kastelli appears to have been destroyed around 220 B.C. Perhaps this followed the demise of Knossos which destroyed completely the neighbouring Lyttos during the same period.

Finally in Kastelli we find remnants from the Byzantine and Venetian era. Part of the Byzantine-Venetian fortification as well as remnants of the Venetian Castle have been found and can be seen in the square of Agios Georgios.