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 Ch. XII THE CRUSADE OF FREDERICK II 445 
suggests that the major portion of the crusaders were simple and lowly. Shortly
after Easter they left England under the leadership of bishops Peter of Winchester
and William of Exeter.57 
 In Lombardy the ancient feud between the cities and the Hohen staufens could
always be easily revived at the slightest evidence of an extension of imperial
authority. A summons for Easter 1226 to a diet at Cremona — ostensibly
to consider the crusade, and to implement the laws against heresy which had
been promulgated at the time of the imperial coronation — occasioned
great unrest and suspicion among the Lombard cities, which now re-formed
the Lombard League. The cities, led by Milan, were declared guilty of breaking
the peace and of hindering preparation for the crusade, and the bishop of
Hildesheim, employing his plenary powers as crusading preacher, placed them
under the ban. The emperor also declared their privileges forfeited and the
terms of the treaty of Constance nullified. With difficulty, Frederick at
last succeeded in obtaining the intervention of the pope. The Lombards yielded
to papal authority, and peace was temporarily restored. The emperor was assured
papal protection of his interests during his absence in the east, and the
Lombards were ordered to obey the imperial laws against heresy and to equip
400 men for a period of two years' service on the crusade. The ban was then
lifted from the cities, the detailed terms of agreement were prepared, and
formal ratification of the document by the various contracting parties was
begun.58 
 But the death of Honorius III on March 18, 1227, before the agreement had
been ratified, enabled the Lombards to ignore the papal command. The new
pope, Gregory IX, forceful, learned, and energetic, included in the letters
announcing his election ringing appeals in behalf of the crusade.59 He admonished
Frederick to fulfill faithfully his crusading vow, warning him in unmistakable
terms of the penalty of the ban. But circumstantial evidence sug gests the
possibility of a secret understanding between the curia and the Lombards.
Moreover, there is no evidence that the 400 fully equipped crusaders from
the towns, required by the papal order, took part in the expedition.60 
 Frederick, however, busied himself with the final preparations 
  Roger of Wendover, Flores historiarum, II, 323 ff.; Annales monasterii
de Waverleia, in Annales monastici (ed. H. R. Luard, vols., 1864—1869,
Rolls Series, XXXV), II, 303. 
 58 For the compromise, see Huillard-Bréholles, II, part a, 703 ff.
See also Röhricht, Beitrâge, I, 15—17. 
  For a brief characterization of Gregory IX see F. Gregorovius, Geschichte
der Stadt Rom im Mittelalter (4th ed., Stuttgart, 1892), V, 138 ff. For detailed
accounts of Gregory see J. Felten, Gregor IX. (Freiburg, 1886), and J. Marx,
De vita Gregorii IX (Berlin, 1889). 
 60 Röhricht, Beitràge, I, 17, n. 91.