The Oxford Dictionary of the Christian Church tells us that Christology is 'the study of the Person of Christ, and in particular of the union in Him of the Divine and human natures'. Not everyone would agree with this definition. And we cannot say whether or not Aquinas would have agreed with it, for he lived before the time when 'Christology' was a word to be listed in dictionaries. But we might well surmise that he would at least sympathize with it were he alive today. That is because Christology, in the sense now in question, is his chief concern when he talks about Christ directly. It is also an area of inquiry in which he draws heavily on what he has to say before he turns to the subject of Christ. His 'Christology' is indebted to his teaching on God considered as Creator and Trinity. It is also bound up with what he thinks about human beings and their natural and supernatural happiness. For he conceives of Christ as the definitive means by which creatures who have come from God return to their source. And he takes him to be the point at which divinity and humanity come closest to each other. For Aquinas's Christ is both truly human and truly divine.
Sticking with the definition of 'Christology' just cited, it is fair to say that many Christologies, both ancient and modern, fight shy of, or even deny, the assertion that Christ is both human and divine. 1 Aquinas, on the other hand, is uncompromisingly orthodox in his teaching about Christ. By this I mean that he accepts without qualification