Revelation
In the beginning of Revelation, it is important to know that John was currently in exile in the island of Patmos, an island in the Aegean Sea and part of Greece’s territory now, because he refused to look at Emperor Domitian as Lord and God. John explains this and he also says he saw the Heavens, so we can suggest that he was writing what he saw while having his revelation or vision —whichever you choose to call it.