I would like to add a note on the word "triumph." This came to my attention when reading Bart Ehrman's "The Triumph of Christianity." His purposeful use of that word - and its use by others at the time - is tied directly to the Roman understanding of that term. We tend to see "triumph" as simply a synonym for "winning." But a Roman triumph was an event celebrating that your enemies were crushed, and they were paraded through the streets in chains. That's a triumph! And that's what's being depicted in this artwork with St. Augustine.
See also https://en.wikipedia.org/wiki/Roman_triumph?wprov=sfla1