This volume continues the authoritative edition of the Acta conciliorum oecumenicorum (ACO) for the ecumenical councils of the first millennium and contains the edition of the proceedings of the VII Ecumenical Council of 787 (Nicaenum II) which dealt with the controversy surrounding the veneration of images. The first part contains a detailed introduction dealing with the transmission of the proceedings and then presents the Greek text of the first three sessions, confronting these with the Latin translation (873) of the Anastasius Bibliothecarius. The detailed critical apparatus also references source texts and critical texts.