Albert Barnes Commentary Daniel 5:21

"and he was driven from the sons of men, and his heart was made like the beasts`, and his dwelling was with the wild asses; he was fed with grass like oxen, and his body was wet with the dew of heaven; until he knew that the Most High God ruleth in the kingdom of men, and that he setteth up over it whomsoever he will." — Daniel 5:21 (ASV)

And he was driven ... - See this fully explained in Daniel 4:25-33.