Germany called young Frederick to the throne, and now Innocent sided with Germany; but he did not live to see the death of Otho and the establishment of the Hohenstaufen.  More decisive was his intervention elsewhere.  Both France and England were laid under interdicts on account of the misdoings of Philip Augustus and John; both kings were forced to submission.  John received back his kingdom as a papal fief.  But Langton, whom Innocent had made archbishop, guided the barons in their continued resistance to the king, whose submission made him Rome’s most cherished son.  England and the English clergy held to their independence.  Pedro of Aragon voluntarily received his crown from the pope.  In every one of the lesser kingdoms of Europe, Innocent asserted his authority.

Innocent’s efforts for a fresh crusade begot not the overthrow of the Saracen, but the substitution of a Latin kingdom under the Roman obedience for the Greek empire of Byzantium.  In effect it gave Venice her Mediterranean supremacy.  The great pope was not more zealous against Islam than against the heterogeneous sects which were revolting against sacerdotalism; whereof the horrors of the crusade against the Albigenses are the painful witness.

Not the least momentous event in the rule of this mightiest of the popes was his authorisation of the two orders of mendicant friars, the disciples of St. Dominic, and of St. Francis of Assisi, with their vows of chastity, poverty, and obedience, and their principle of human brotherhood.  And in both cases Innocent’s consent was given with reluctance.

It may be said that Frederick II. was at war with the papacy until his death in the reign of Innocent III.’s fourth successor, Innocent IV.  With Honorius the emperor’s relations were at first friendly; both were honestly anxious to take a crusade in hand.  The two were brought no further than the verge of a serious breach about Frederick’s exercise of authority over rebellious ecclesiastics.  But Gregory IX., though an octogenarian, was recognised as of transcendent ability and indomitable resolution; and his will clashed with that of the young emperor, a brilliant prince, born some centuries too early.

Frederick was pledged to a crusade; Gregory demanded that the expedition should sail.  Frederick was quite warranted in saying that it was not ready; and through no fault of his.  Gregory excommunicated him, and demanded his submission before the sentence should be removed.  Frederick did not submit, but when he sailed it was without the papal support.  Frederick endeavoured to proceed by treaty; it was a shock to Moslems and to Christendom alike.  The horrified Gregory summoned every disaffected feudatory of the empire in effect to disown the emperor.  But Frederick’s arms seemed more likely to prosper.  Christendom turned against the pope in the quarrel.  Christendom would not go crusading against an emperor who had restored the kingdom of Jerusalem.  The two came to terms.  Gregory turned his attention to becoming the Justinian of the Church.