Adam Clarke on Revelation 16:11

Blasphemed the God of heaven - Neither did they repent; therefore other judgments must follow. Some think that the sun was Vitellius, the Roman emperor, and that his throne means Rome; and the darkening refers to the injuries she sustained in her political consequence by the civil wars which then took place, from which she never entirely recovered. Others apply it all to papal Rome, and in this respect make out a very clear case! Thus have men conjectured, but how much nearer are we to the truth?