This chapter studies the decline and disappearance of the ecumenical synods in late antiquity. As agonistic festivals were the raison d’être of the ecumenical synods, their fate was intertwined with that of the agonistic network. The fourth century ad saw a gradual unravelling of the festival circuit, due to financial problems, socio-political changes in the Greek poleis and changing mentalities and habits. As a result, evidence on the ecumenical synods declines sharply from the late third century on. Important sources discussed here are a tetrarchic rescript on the privileges of competitors, issued in response to a request of the two synods, and a long and complex inscription from ad 313 that was erected in the xystic synod’s headquarters and dealt with a donation by a rich family. This chapter refutes the opinion of some earlier scholars who argue that the synods were absorbed by the circus factions. Rather, it appears that they remained tied to the world of traditional Greek agonistics and that they disbanded when the last of the important Greek agones ceased to be held, that is by the 420s ad at the latest.