Calvin says that Henry VIII was a monster [on Hosea 1.3-4]:
In short, the reformation under Jehu was like that under Henry King of England; who, when he saw that he could not otherwise shake off the yoke of the Roman Antichrist than by some disguise, pretended great zeal for a time: he afterwards raged cruelly against all the godly, and doubled the tyranny of the Roman Pontiff: and such was Jehu.
When we duly consider what was done by Henry, it was indeed an heroic valour to deliver his kingdom from the hardest of tyrannies: but yet, with regard to him, he was certainly worse than all the other vassals of the Roman Antichrist; for they who continue under that bondage, retain at least some kind of religion; but he was restrained by no shame from men, and proved himself wholly void of every fear towards God. He was a monster, and such was Jehu.
He thought that kings of his day had poor judgement generally [on Daniel 6.3-5]:
But now kings think of nothing else than preferring their own panders, buffoons, and flatterers; while they praise none but men of low character, whom God has branded with ignominy. Although they are unworthy of being reckoned among mankind, yet they esteem themselves the masters of their sovereigns, and treat the kings of these days as their slaves.
His opinion of Catholic Bishops was not any higher [on Ezekiel 3.16-17]:
What Ezekiel heard belongs to all teachers of the Church, namely, that they are Divinely appointed and placed as on watch-towers, that they may keep watch for the common safety of all. It was the duty of those who have been appointed from the beginning ministers of the heavenly doctrine to be watchmen. And would that in the Papacy, as this name has been imposed on idols, dumb and blind and deaf, those who with swelling cheeks call themselves Bishops, had been admonished of their vocation. For we know that the word Bishop means the same as watchman. But when they were boasting themselves to be bishops, they were drowned in the darkness of gross ignorance: then also they were buried in their pleasure, as well as in sloth, for there is no more intelligence in these animals than in oxen or asses. Asses and oxen do spend their labor for the advantage of man, but these are not only destitute of all judgment and reason, but are altogether useless.