Eusebius of Caesarea, on Isa 1:1

“The vision of Isaias the son of Amos I which he saw concerning Juda and Jerusalem in the days of Ozias, Joathan, Achaz, and Ezechias, kings of Juda.”

“[The heading] indicated the ages of the kings, since there was a different state of affairs among the Jews, and events were to transpire in the distant future which never entered the mind or suspicion of the people of that time. Furthermore, it needs to be noted that the whole book, which only seems to be a single composition, was actually spoken over long periods of time, since there was need of extensive and precise understanding to discern the future, to determine the meaning of the events of the time and to suit the prophecy for the events that occurred in each reign. For the age of these kings covered fifty years in all, during which the things contained in this whole book were spoken.”

Imported from an open dataset — not yet checked against the printed edition.