The stone roof of the Tholos of Athena Pronaia in Delphi: structural hypotheses starting from fragments of marble tiles

This contribution aims at developing a complex multidisciplinary research topic, the study of stone reciprocal structures from a geometrical and structural point of view. The starting point of this research is the fascination exerted by some mysterious objects belonging to the architecture of ancient Greece, i.e., fragments of marble tiles belonging to the roof of the tholos of Athena Pronaia in Delphi, dated back to the first decades of the 4th century BC. According to Vitruvius (De Architectura), it was one of the most important architectures of the classical period, probably designed by the architect Theodoro of Phocaea. Made of marble coming from Attica, with twenty columns of Doric order on the outside, this temple was considered one of the architectural wonders of the world for the algebraic complexity of the geometrical structure, matched in detail and perfection by its decoration. Despite the number of studies on this sanctuary, the poor state of preservation and lack of original material did not allow scholars to perform concluding research on its original configuration, with reference to the reconstruction of the roof