Charles Ellicott Commentary Daniel 4:1

"Nebuchadnezzar the king, unto all the peoples, nations, and languages, that dwell in all the earth: Peace be multiplied unto you." — Daniel 4:1 (ASV)

Peace ...—For this mode of address, compare Ezra 4:17; Ezra 7:12. The date of the events recorded in this chapter cannot be determined, as a gap exists in the historical record for the last eighteen years of Nebuchadnezzar’s reign. The only facts that occurred during this period, so far as is known, are the terrible form of mania from which the king suffered, due to which he was kept under restraint for some time, and the further extension of his dominions after his recovery (Daniel 4:34).

All the earth— By this time the king has become so powerful that he regards himself as universal monarch, so that some time must have elapsed since the events mentioned in the last chapter.