As most of the treasuries, the treasury of the Athenians is a small building in Doric style, in the shape of a temple in antis; it is made of Parian marble. The relief decoration, going back to late Archaic period is of high quality, very elegant with the sense of analogy and vigorous movement.
The relief of the frieze of the back – northern – façade presents the labors of Hercules, whereas this of the front – southern – façade depicts the achievements of Theseus. Placing the two major heroes side by side, the Athenians intended to underline the importance of the establishment of democracy in their city-state. The terrace on which the building stands leaves a triangular free space at the south, at the main façade; it is there that the Athenians used to display the spoils from the battle of Marathon and other trophies, during the official feasts and great processions that took place at Delphi. The walls of the building are inscribed with important texts, still surviving; it is a precious source of information for the customs, the feasts and the four official processions that the Athenians celebrated at Delphi, the Pyrphoria, the Tripodiphoria, the Pythais and the Dodecais. We also get information about ancient music, thanks to two inscriptions, the only ones of this kind found so far, reciting the famous hymns to Apollo and accompanied with music annotations. Today the texts are displayed in the Archaeological Museum of Delphi. Moreover, inscriptions are found inside the treasury; they contain important honorary decrees dated in the 3rd century BC and later; some inscriptions cite the names of pawnbrokers who used the premises during the Roman period.