Calvin here refers to Luther with the name “Pericles,” an acknowledgement of Luther’s great significance and polemical power. Pericles was an immensely important Athenian statesman / orator who lived between the Persian and Peloponnesian wars. That whole period is sometimes called the “Age of Pericles.” Calvin considers Luther to be the Pericles of his age.
Letter of John Calvin to Philip Melanchthon in June of 1545, as represented in John Calvin, John Calvin: Tracts and Letters, 4.466-8.
If the matter stands as the Zurichers say it does, then they have just occasion for their writing. Your Pericles allows himself to be carried beyond all due bounds with his love of thunder, especially seeing that his own case is by no means the better of the two. We all of us do acknowledge that we are much indebted to him. Neither shall I submit myself unwillingly, but be quite content, that he may bear the chief sway, provided that he can manage to conduct himself with moderation. Howbeit, in the Church we must always be upon our guard, lest we pay too great a deference to men. … But, you will say, his disposition is vehement, and his impetuosity is ungovernable; --as if that very vehemence did not break forth with all the greater violence when all shew themselves alike indulgent to him, and allow him to have his way, unquestioned. … Consider, besides, whether the Lord may not have permitted you to be reduced to these straits in order that you may be brought to a yet fuller confession upon this very article. It is indeed most true, as I acknowledge it to be, that which you teach, and also that hitherto, by a kindly method of instruction, you have studiously endeavoured to recall the minds of men from strife and contention. I applaud your prudence and moderation. While, however, you dread as you would some hidden rock, to meddle with this question from the fear of giving offence, you are leaving in perplexity and suspense very many persons who require from you somewhat of a more certain sound, on which they can repose. … Perhaps, therefore, it is now the will of God thus to open up the way for a full and satisfactory declaration of your own mind, that those who look up to your authority may not be brought to a stand, and kept in a state of perpetual doubt and hesitation. These, as you are aware, amount to a very great number of persons.