Innocent accepted the guardianship of Frederic, and historians comment severely on his next step. In spite of all his fiery letters to the southern clergy and people--even to the Saracens[240]--inciting them to resist the Germans, Markwald made considerable progress. Then there came to Rome a certain French adventurer named Walter de Brienne, who had married a daughter of Tancred of Sicily. Tancred had, on resigning Sicily, retained Lecce and Tarentum, and Walter claimed these as his wife's inheritance. Whether or no Innocent had actually promoted the marriage and invited Walter to Italy[241] we cannot confidently say, but it was assuredly dangerous to let such a man get a footing in southern Italy; it was probable enough that he would eventually claim the whole kingdom taken from Tancred. However Innocent blessed and financed his enterprise, on the formal condition that he would respect the rights of Frederic, and soon had a French troop waging more effective war upon the Germans. The struggle ceased with the death of Markwald in 1202, and of Walter in 1205, and Innocent then pressed a design of marrying the young Frederic to Constanza of Aragon. For the time Frederic's rights were respected, but there can be no doubt that these early years spent amidst intrigue and treachery contributed to the development of his anti-clerical spirit. There was, in fact, a good deal of anti-clericalism growing in Italy. The development of civic and communal life and the comparative enlightenment which was spreading turned many critical eyes on the Roman system. Heresy descended the Alps and found favour in the free cities; even, at times, in Papal cities. I have described how Viterbo was crushed by the Roman troops. Innocent intervened in its favour, after its defeat, and he was then outraged to learn that Viterbo was, like many other cities, appointing heretics (the Cathari) to high places. He spent the summer of 1207 in Viterbo, and enforced very stringent rules for the repression of heresy. These laws were extended to all the Papal dominions, but we shall see the Pope's attitude more clearly when we deal with the crusade against the Albigensians. Innocent was not less emphatic in denouncing the incessant wars of the rival cities, and his correspondence is largely occupied with his endeavours to secure their feudal allegiance to Rome.