In their later, more decadent period, the Romans became expert at building new monumental structures by recycling parts from previous ones. Known as spolia, it creates a pretty hodge-podge effect at times, with disparate architectural elements cobbled together into an arch, for example, the one for Constantine. That’s the excuse for me desecrating this fantasy landscape. I’ve incorporated my spolia. How like me to take something and spoil (exploit) it.
The head capital looks like Pompey the Great to me or maybe the monumental head of Constantine. Take your pick.