Yes, the book of Jonah. The Sailors who were more familiar with Judaism started worshiping YHWEH, the God of Israel. When he got to Nineveh, they were converted to GOD. History tells us that at this time the entire Assyrian Empire had a religious revival with a form of monotheism; but they were worshiping the God that they understood to be the Most High God.
In Daniel we learn of Nebuchadnezzar's conversion; Historically we find that Nebuchadnezzar did have 7 years where he became like Howard Hughes, but then he regained his senses and became a much kinder person a much more religious person, but a faithful worshiper of who the Babylonians saw as the Most High God.