The nonagon as a tool for the drawing of the Roman Theatre of Lecce

The signs of the Roman city of Lupiae, current Lecce, are many and among them the most noteworthy is the Roman Theatre. The monument has been accidentally discovered during the excavations for the foundations of a house in 1929 and it is located short distance from another landmark of the Roman Lecce: the amphitheatre. The chance of utilizing a the latest threedimensional technology for the detection of the ruins was an opportunity to study the model of the survey obtained. The analysis of the latter reveals a mismatch with the instructions in “De Architectura” by Vitruvius and shows a particular use of the nonagon for the design of its iconography. This study aims to compare the hypothesis obtained from the analysis of the metrological survey with the rules explained in the work of Vitruvio to underline similarities and differences between theory and practice.