On the south of the Mosque you will find one of the most important buildings of the archaeological site of Paleopolis, the Sanctuary, within which the initiation to the Mysteries took place.
The sanctuary was built in the last quarter of the 4th century BC (around 325 BC) and it seems that it replaced two old arched buildings, one of the archaic and one of the 5th century BC. The completion of the construction of the sanctuary took place almost two centuries later, when the Doric facade and the sculptural decoration of the pediment and the capes were added. The construction of the sanctuary is probably because of the interest of the king of Macedonia Philip B’ took in it.
It is a rectangular, oblong Doric temple, measuring 40 X 13 m. The façade consists of two rows of six columns. In 1956 the columns and the central architraves of the front of the sanctuary were restored with the financial support of the Bollingen Foundation.
In the north pediment the theme of the sculptural decoration was the upbringing of Aetion with emphasis on the heroic figures who initiated the rituals of Samothrace, while in the south there were probably the busts of the great gods.
The floor was made of marble and the walls were coated with gold. There was a double row of marble seats for those attending the ceremonies. In the center of the northern part there was an opening, which was used for offerings, while the southern part formed an arch with a wooden roof.
On the east wall of the building, on the outside, there were two marble pedestals, which surrounded a base with a torch and were probably associated with the ceremony.