I’ve been thinking about this question a lot. A question of this type gets posted every month or two, and always goes unanswered. I have a suspicion about why it goes unanswered, and that’s actually going to be the bulk of my post.

The short answer to your question is that the ‘Romans’ didn’t write about ‘their guilt’ in crucifying Jesus in the post-Constantine or post-Theodosian contexts. As far as I’m aware, and I consider myself fairly well versed in Christian-related writings from the 4th and 5th centuries, there are no texts that give this sustained consideration.

But why do people keep asking this? And why doesn’t anybody answer? These are related problems because the question itself is problematic. Even if you, OP, didn’t necessarily buy in to the assumptions I’m about to outline, I think these assumptions are problematically pre-supposed by the form of the question.

In the 1st century we tend to think of ‘Roman’ Romans. What I will call ‘Latinate Romans’ for the sake of this answer. That is, Roman identity in the C.1st both AD and even moreso BC is constructed around Latin-speaking Rome-the-city homogeneity. Pontius Pilate emerges out of that milieu, and so do the early emperors. We think of the Romans as a mass entity, even though it’s not really true of that period. And so, particularly from the marginal position of Judea and the early Christian writers of gospel-texts, the ’Romans’ are an other-entity.

But in the 4th century, first when Constantine becomes sole emperor and legitimises Christianity, and later when Theodosius makes Nicene-Christianity the state religion, ‘Roman’ identity is not so Latinate. Rome is not the centre of the empire except in a symbolic and heritage sense. After the 3rd century crises, when Diocletian sets up the tetrarchy, not a single emperor bases themselves in Rome. The weight of power and prestige is firmly in the East. ‘Romans’ are not the same kind of mass entity that they were, and in fact they never were anyway, but they are far less so than before. So the sense of mass-entity continuity that we want to construe between 1st C. Romans and 4th century ones just doesn’t exist. More than that, the narrative of continuity of statehood and culpability that we might perceive, also doesn’t function in the same way. Constantine and Theodosius, and those in-between, don’t appear to construct themselves as responsible for the actions of past emperors, particularly the way that emergent narratives of imperial power function in Christian thinking (see Eusebius of Caesarea’s treatment of Constantine for this in particular).

So, ‘Romans’ don’t think of themselves as “the Romans” at least in the sense that they need to talk about or deal with ‘blame’ assigned to “Romans” in the gospel narratives. They do need to deal with guilt and sin and crucifixion, but not in a way that is transmitted through a mass-entity-identity or continuative-state-guilthood.

Which is why this theme appears, to me, so absent in 4th and 5th century texts, and also why no-one answers this question – because no-one feels like they know the answer, or knows enough about the situation to answer it. It’s always more difficult to answer “no, because there’s no evidence”, but that’s what I’m suggesting, and I’m suggesting that the question is mis-framed which is why it goes answerless.