The City Eleusinion was one of the most important sanctuaries in the religious life of the ancient Athenians. As the urban "branch" of the sanctuary of Demeter and Kore at Eleusis, the City Eleusinion played a key role in the initial stages of the Greater Mysteries held each fall in the month of Boedromion (corresponding to September in the modern calendar). This festival commemorated Demeter's search for and reunification with her daughter Kore (Persephone), who had been abducted by Hades/Plouton and taken to the Underworld. Those initiated into the Mysteries were promised a better condition in the afterlife. Originally open only to Greek men and women, the Eleusinian Mysteries later included foreigners who spoke Greek, and eventually became one of the most famous religious festivals in antiquity. It is likely that City Eleusinion was also one of multiple locations in Athens used for celebrations of the Thesmophoria, an ancient festival of Demeter and Kore celebrated throughout the Greek world but open only to the women of each community. In contrast to the Eleusinian Mysteries, which centered on a shared religious experience and hope for a better afterlife, the festival of the Thesmophoria focused more directly on rituals designed to guarantee the fertility of both women and crops.