‘Under the Mediterranean’ The Honor Frost Foundation Conference on Mediterranean Maritime Archaeology 20th 23rd October 2017 Short Report Series. doi: https://doi.org/10.33583/utm2020.07 © 2020 The Author The Tonnage of the Syracusia: a metrological reconsideration Dr Emmanuel Nantet Leon Recanati Institute for Maritime Studies, University of Haifa, Israel The tonnage of the Syracusia, the biggest ship built in the ancient Mediterranean, has been much discussed by scholars. Indeed, the various merchandise the ship carried are detailed by Athenaeus, who relies on a text previously written by Moschion. However, the value of the units of measurements used in Athenaeus’ account are not well known. So far, scholars have suggested only either Athenian or Roman units of measurement. The present report aims at exploring the possibility of local metrological systems, such as Ptolemaic or Sicilian ones, as Moschion and Athenaeus respectively lived in Sicily and in Alexandria. Key words Metrology, tonnage, cargo, wheat, giant ship, Sicily The Syracusia is known as the biggest ship built in ancient times (5, 206d-209e). The ship was built by Archias of Corinth, to fulfill an order from king Hiero II (269215 BCE). The construction was supervised by Archimedes (Salviat, 1987; Zevi, 2001; Pomey & Tchernia, 2006; Castagnino Berlinghieri, 2010; Nantet, 2016:12131). Big the ship certainly was, but how big exactly? Many scholars have focused on that giant ship in order to assess the maximum tonnage allowed by the construction techniques in Hellenistic times (Rougé, 1984; Casson, 1971; Pomey & Tchernia, 1978). Of course, the contents of the cargo are precisely described (Athenaeus, Deipnosophistae, 209a): Σίτου δὲ ἐνεβάλλοντο εἰς τὴν ναν μυριάδας ἕξ, ταρίχων δὲ Σικελικν κεράμια μύρια, ἐριν τάλαντα δισμύρια, καὶ ἕτερα δὲ φορτία δισμύρια.