The Romans, from the absence of the pope, and from the emperor being in Lombardy, had reacquired some authority in Rome, and proceeded to recover the obedience of those places which had been subject to them. And as the people of Tusculum refused to submit to their authority, they proceeded against them with their whole force; but these, being assisted by Frederick, routed the Roman army with such dreadful slaughter, that Rome was never after either so populous or so rich. Alexander now returned to the city, thinking he could be safe there on account of the enmity subsisting between the Romans and the emperor, and from the enemies which the latter had in Lombardy. But Frederick, setting aside every other consideration, led his forces and encamped before Rome; and Alexander fled to William, king of Puglia, who had become hair of that kingdom after the death of Roger. Frederick, however, withdrew from Rome on account of the plague which then prevailed, and returned to Germany. The cities of Lombardy in league against him, in order to command Pavia and Tortona, which adhered to the imperial party, built a city, to be their magazine in time of war, and named in Alexandria, in honor of the pope and in contempt of Frederick. Guido the anti-pope died, and Giovanni of Fermo was appointed in his stead, who, being favored by the imperialists, lived at Montefiascone. Pope Alexander being at Tusculum, whither he had been called by the inhabitants, that with his authority he might defend them from the Romans, ambassadors came to him from Henry, king of England, to signify that he was not blamable for the death of Thomas à Becket, archbishop of Canterbury, although public report had slandered him with it. On this the pope sent two cardinals to England, to inquire into the truth of the matter; and although they found no actual charge against the king, still, on account of the infamy of the crime, and for not having honored the archbishop so much as he deserved, the sentence against the king of England was, that having called together the barons of his empire, he should upon oath before them affirm his innocence; that he should immediately send two hundred soldiers to Jerusalem, paid for one year; that, before the end of three years, he should himself proceed thither with as large an army as he could draw together; that his subjects should have the power of appealing to Rome when they thought proper; and that he should annul whatever acts had been passed in his kingdom unfavorable to ecclesiastical rule. These terms were all accepted by Henry; and thus a great king submitted to a sentence that in our day a private person would have been ashamed of. But while the pope exercised so great authority over distant princes, he could not compel obedience from the Romans themselves, or obtain their consent that he should remain in Rome, even though he promised to intermeddle only with ecclesiastical affairs.