Note 170 — Chapter XXVII · ToC

There were often two emperors, one in the East, the other in the West, but there was but one empire. The two emperors, though they may have resided, one in Constantinople and the other in Italy, were considered as being but one person. In addressing one of them the word "you" (in the plural) was used, as if both were addressed at the same time. This was the first use of the pronoun of the second person in the plural for such a purpose; for throughout antiquity even kings and emperors were addressed in the singular.