Small wonder that after three months his public lectures were brought to an end and he returned to London. Here he made several friends, among them Sir Philip Sidney, the poet-soldier, of whom he had already heard in Italy, for Sidney had studied at Padua. Fulk Greville, who described himself on his epitaph as “Servant to Queen Elizabeth, Councilor to King James, and friend to Sir Philip Sidney,” also became intimate with him, and at his house Bruno held a second disputation, at which he again seems to have aggravated his hearers. He had a sincere admiration for Sidney and dedicated a book of sonnets to him. The protection given to him by Queen Elizabeth he repaid by referring to her in his poems in terms of the highest flattery, which no doubt she appreciated. But this praise of a Protestant Queen, who herself was excommunicated, was eventually brought against him by his judges. He was greatly impressed by the beauty and bearing of English women and by “the Briton’s terrible energy, who, regardless of the stormy deep and the towering mountains, goes down to the sea in ships mightily exceeding Argonautic art.” After two years in England he returned to Paris with the French Ambassador, who, he says, “saved him from the Oxford pedants and from hunger.” But he did not stay long in Paris, “because of the tumults,” and proceeded on his wanderings into Germany.
At Marburg, the rector of the University refused Bruno permission to hold public disputations on philosophy, at which, the rector himself says, “he fell into a passion of anger and he insulted me in my house.” No doubt he made it very unpleasant for any one who attempted to thwart him, for he was headstrong and impetuous. At Wittenberg he was permitted to enter his name on the lists of the University, and also to give private lectures. The professors of Toulouse, Paris, and Oxford, he declared, received him “with grimaces, upturned noses, puffed cheeks, and with loud blows on the desk,” but the learned men of Wittenberg showed him courtesy and left him in peace. In fact, he was able to remain there working for two years, until, owing to the feud between the Lutherans and the Calvinists, in which the latter got the upper hand, he found himself compelled to quit the city. On his departure he pronounced a great oration in praise of wisdom, which malicious public opinion described as a speech in favor of the devil.