Solomon
The Biblical king of Israel shows up as a character in this text for the reason he shows up as a character in any other text. There is one aspect of Solomon’s famed “wisdom” that is noted here that does not pop up in other references. How did Solomon acquire his great wisdom? From God while Solomon slept. Thus, he is situated also as an example of how grace is sometimes bestowed without any exercise of free will.
Boethius
Boethius was a Roman senator and 6th century philosopher. He once declared himself the King of Italy. He would go on to become one of those who attain great fame as a consequence of writing from his jail cell. The Consolation of Philosophy is the guiding force in the life of Ignatius Reilly, legendary protagonist of A Confederation of Dunces. Aquinas does not seem to share Reilly’s view: he is constantly criticizing the definitions provided by Boethius as lacking.
Jesus Christ
The entire point of the text is to offer a point-by-point breakdown of Christian theology. This is essentially a textbook for Christianity, and from the length of it, one intended to be used throughout all the required years of seminary school. If after reading this volume anyone still has some questions about the theological implications of Christ, it may be time to just give up on the whole matter.
The Master
At various points in the text, the author makes reference to the Master with a capital letter as opposed to the occasional general use of “the master.” In the case of the capitalized Master, Aquinas is responding specifically to Peter Lombard and, more precisely, to Lombard’s assertions in his own theological textbook, The Sentences which was the dominant type of this text for the previous two centuries or so.
