The reverence and admiration of the Roman emperors, initiated or not, towards Demeter and Kore was expressed through significant donations to the Eleusinian sanctuary. Emperor Hadrian, in particular, was distinguished for his intense devotion and love for the Mysteries. During his imperial visits to Greece, he actively participated in the processions (in 124/125, 128/129, and 131/132 AD), and contributed to the upgrading of the Sacred Way by financing the construction of an imposing stone bridge over the Eleusinian Kifissos, making the river crossing safe for the procession.
The two imposing single-arched arches that were constructed on both sides of the Roman courtyard are tangible evidence of Hadrian’s contribution to the sanctuary. Similar to the eastern triumphal arch, an identical one was erected on the western side of the paved courtyard, marking the beginning of the road to Megara. It replicated the arch that Hadrian had built in Athens to separate the ancient city from the new Roman one. It is constructed of Pentelic marble and was supported by Corinthian pillars flanked by Corinthian columns. These columns were placed on square bases adorned with the symbols of Demeter and Persephone, the crossed torches. The central upper part of the arch was tripartite and framed by Corinthian columns, with a pediment reminiscent of a small temple. There, most likely, bronze statues of the imperial families would have been placed. The total height of the arch is 16 metres.
As in the eastern arch, the epistyle of the arch bears the dedicatory inscription: “THE PANHELLENES TO THE GODDESSES AND THE EMPEROR”. The inscription refers to the Panhellenion, a union of Greek states founded by Hadrian around 131–132 CE. Closely associated with the imperial cult and the Eleusinian Mysteries, its members sent offerings to Eleusis and possibly undertook the financial supervision of the ceremonies.
