Sacred well Sant’Anastasia, Sardinia (Pozzo Sacro Sant’Anastasia, Sardegna)

Abstract

Archeoastronomy as the science of using the Universe, planets, sun or moon their positions and relations in space, with visual traces on Earth, is important also in architecture.
Some of waterwells were constructed by means of a construction system called corbelling, in which horizontal layers – in a dry stone walling system overlap each other. It can be in a longitudinal shape (in staircases) or in circular form (in central rooms, called a false dome).
Sant’Anastasia ‘pozzo sacro’ is a circular stone construction in corbelling, with a staircase covered by corbelled elements. Its orientation is north-south Citizens of Sardara use its water by means of an electrical pump but the original level of the water would have been to the first stair, about 75 centimetres. Archaeologists date the well in Sardara to the 12th century BC, to the Nuraghic culture (1700 BC to 238 BC).
Twice a year, the sun’s rays pass through the staircase to the water level and are reflected back again through the circular opening in the top of the corbelled false dome. At the same time, the sun enters through the top opening of the chamber into the dome, touching the water surface. The angle of the construction means that it happens twice a year, on April 21 and at the end of August. The sun merging with the water and a sunbeam simultaneously rising out of the ground certainly provide a miracle.
There are five pieces of evidence of this: physical phenomena, the naming of the medieval church after the pre-Christian well, the name originates from ‘anastasos’ or ‘ressurection’, miracle occurs twice a year, and it happens every year on the saint’s name day.