The description of the arrival of Constantius II in Rome is well done - and you held my attention nicely with the last sentence of that first paragraph (an effecive contrast with the previous lines). In the triumph, I enjoyed another contrast, between how the sons of Phocas appeared to onlookers and how they seemed to people who knew them. (In the sentence in the final paragraph which began "There were men who had been impressed by his promises", I was slightly distracted by the use of 'in their mind' and then 'in mind' in the same sentence, but this is a small issue and it may just be me).

You've got me wondering if the prediction by those who aren't impressed with Phocas will become a self-fulfilling prophecy - will muttering lead to plotting?