Re-evaluations of the category of deponency in recent years have been the leading cause of a paradigm shift taking place in studies on the ancient Greek voice system, opening up new avenues for further remodelling. The present study contends that verbal voice operates according to an ergative two-voice system, active and middle-passive, producing two contrastive roles the subject plays in a clause. Within a nominativeaccusative alignment patterning, which marks out transitive operations of a clause, ergative functions centered on verbal voice are present in the language’s verbal morphology and syntax. An ergative view of voice specifies different transitive participant roles and focuses on the affected element of the clause that realizes or actualizes the verbal process. Clearer expression of the subject’s function in the clause occurs by distinguishing between two opposing roles: the subject functioning either as realization of the process or as cause of the process. Two basic and contrastive roles of the subject, therefore, mean that two semantic domains for voice are operational in the language system network despite the occurrence of three morphological forms in the aorist and future tense-forms. The middle and passive uses, together comprise the middlepassive voice, and the active voice comprises the other voice domain. Middle and passive functions share the common feature of subject-affectedness, but middle uses occur when there is a feature of internal agency in addition to the subject actualizing the verbal process. Passivity occurs when the subject actualizes the verbal process with an added feature of external agency to the clause. Moreover, passivity takes place through specific grammatical constructions within the middle-passive voice that operate as agentive augmentations (specified or not) of a middle-passive clause type. This is frequently expressed using the so-called, ‘passive marker,’ -(θ)η, that was encroaching upon middle forms during this stage of the language and gradually expanding its range of function in the New Testament writings. / Thesis / Doctor of Philosophy (PhD)