Final answer:
The Synod of Hippo in 393 AD was the first to approve Athanasius' canonical list of books for the New Testament, not the Council of Nicaea which dealt with theological debates such as Arianism.
Step-by-step explanation:
The first council/synod to approve Athanasius' canonical list was the Synod of Hippo in 393 AD.Although the Council of Nicaea in 325 AD was the first ecumenical council and addressed key theological disputes, such as the Arian controversy, it did not endorse a canonical list of books for the New Testament. The first ecclesiastical body to formally recognized Athanasius' list of canonical books, which he put forth in his festal letter around 367 AD, was the Synod of Hippo, followed by the 3rd Synod of Carthage in 397.
It's important to recognize that there were numerous ecumenical councils, such as the Councils of Nicaea, Constantinople, Ephesus, and Chalcedon, which shaped Christian dogma over the centuries, but the specific task of delineating the canon of scripture fell to local synods like those at Hippo and Carthage.