Which is exactly the point I was making. For a particular emperor in Constantinople, paying tribute to an army outside the wall may have been, or appeared to ha

Which is exactly the point I was making. For a particular emperor in Constantinople, paying tribute to an army outside the wall may have been, or appeared to have been, an economical option for achieving their personal goals, which may not have been aligned with the empire's, and thus the fact the action occurred can not be taken as evidence that it was a rational choice which served the interest of the Roman Empire. People in the past weren't dumb, but they weren't hyper-competent nor devoid of ulterior motives either. We should expect most past decisions to have been sub-optimal.