The tower of Agia Triada – or tower of Vasilis – is the best-preserved ancient monument on Amorgos and the best-preserved tower of that kind in the Cyclades. It is located in the district of Arkesini, near the settlement “sto Chorio”, built on a low hill. It is a fortified residence with a rectangular tower (5.60 m high nowadays) and a yard (25.31 x 11.40 m). Although already known since the 19th century thanks to the Bavarian Hellenist Ludwig Ross, the monument has not yet been excavated. In the yard, we can still see remnants of walls marking the different rooms. What is known from the interior of the tower is a stone staircase leading up to the first floor, as well as some triangular windows and two conches. Mobile findings evince this site was used from the 3rd millennium BC up to the Modern times. The tower itself dates approximately from the late 4th century BC. Remnants of farm houses dating from the 4th century BC up to the 7th century AD have been found to the east of the tower, as well as a building complex of the Modern period, also used in farming activities.
This was obviously a defensive tower, as demonstrated by its meticulous masonry, solid construction and the elevated building. Thanks to its location, it could control access to both Arkesini and its port, and also communicate with other towers through a system of light signals. At the same time, it protected the surrounding farmhouses and was an organized residence with storage rooms for farming products and tools. Who built it is still unknown, but it was most likely built by some wealthy resident of Arkesini, since the city during Hellenistic Times, as demonstrated by inscriptions, could not afford to erect such buildings.