The polygonal retaining wall was built by the Athenians. The construction technique known as lesbian, named after its origin from the island of Lesbos, was a very expensive and difficult technique. The purpose of the wall was to retain the ground from the temple above. It is covered with more than 800 inscriptions, most of which were manumissions of enslaved men, especially from the period between 300 to 100 BC. This way the people liberated the enslaved ones by offering them to God Apollo. The cost of manumission was paid by the slaves themselves. 60% of the inscriptions concern enslaved women.