A crusader excommunicated by the Head of Christendom first for not fulfilling his vow and then for fulfilling it! This was a degrading and ridiculous sight; and Frederick, now definitely hostile to Rome, continued on his way, determined with obstinate pride that, if not for the Catholic Faith, then for his own glory, he would carry out his purpose. The Templars refused him support: the Christians still left in the neighbourhood of Acre helped him half-heartedly or stood aloof, frightened by the warnings of their priests; but Frederick achieved more without the Pope’s aid than other crusaders had done of late years with his blessing. By force of arms, and still more by skilful negotiations, he obtained from the Sultan possession of Jerusalem, and entering in triumph placed on his head the crown of the Latin kings.
His vow fulfilled, he sailed for Sicily, and the Pope, whose troops in Frederick’s absence had been harrying ‘the Kingdom’, hastily patched up a peace at San Germano. ‘I will remember the past no more,’ cried Frederick, but anger burned within him at papal hostility. ‘The Emperor has come to me with the zeal of a devoted son,’ said Gregory, but there was no trust in his heart that corresponded to his words.
A Hohenstaufen, who had taken Jerusalem unaided, supreme in Naples, supreme also in Germany, stretching out his imperial sceptre over Lombardy! What Pope, who believed that the future of the Church rested on the temporal independence of Rome, could sleep tranquilly in his bed with such a vision?
It is not possible to describe here in any detail the renewed war between Empire and Papacy that followed the inevitable breakdown of the treaty of San Germano. Very bitter was the spirit in which it was waged on both sides. Frederick, whatever his intentions, could not forget that it was the Father of Christendom who had tried to ruin his crusade. The remembrance did not so much shake his faith as wake in him an exasperated sense of injustice that rendered him deaf to those who counselled compromise. Unable to rid himself wholly of the fear of papal censure, he yet saw clearly enough that the sin for which Popes relentlessly pursued him was not his cruelty, nor profligacy, nor even his toleration of Saracens, but the fact that he was King of Naples as well as Holy Roman Emperor.