After his meeting with Frederick in September 1230 and more or less for the first time since the beginning of his papacy, Gregory did not stand at odds with the imperial ruler of the Christian world. Once again, Frederick had become a beloved son who had chosen the way of peace, resuming his proper duties to serve and defend the Roman church. Over the following years Gregory would repeatedly emphasize the theme of harmonious unity between the two powers or the two swords, the spiritual and the material, making common cause for the defense of the faith, the protection of the papal patrimony, and the proper ordering of the church. As the Vicar of Christ, who was responsible for preserving and fostering the peace, he identified a number of challenges and projects that called for the emperor’s assistance one way or another: settling the persistent strife on the Italian peninsula, above all in Lombardy; dealing with the imperiled conditions of the Holy Land; and combating the threat of heresy within the body of the faithful. When the Romans tried to cast off papal lordship and attacked neighboring communities that belonged to the Papal States, the pope even called for imperial assistance against the rebellious citizens of his own city.6
Rather than an elaborate ruse that masked the inevitable return of antagonism between Gregory and Frederick, these years of relative peace and cooperation in their relationship revealed the potentialities of public cooperation between the two powers in ways rarely seen before.7 Frederick openly embraced his role as a “spiritual son” of the Roman church, its defender against infidels, heretics, and other enemies. Such obligations did not imply political subordination to the Vicar of Christ; they represented the fulfillment of his exalted position. In its preamble, the Constitutions of Melfi make this claim clear. As part of the “stewardship” granted to them by the Lord, rulers should not allow the “Holy Church, the mother of the Christian religion” to be “defiled by the secret perfidies of slanders of the faith.” Rather, “they should protect her from attacks of public enemies” by the power of the “material sword” and “preserve peace,” the sister of justice. The law code reaffirmed the prince’s commitment to fight against heretics and his drawing the “sword of righteous vengeance against them,” preventing their hostile attacks against the Roman church, “the head of all other churches, to the more evident injury of the Christian faith.” Judged guilty of “public crimes,” heretics would face the loss of their property and capital punishment, while their accomplices would suffer dispossession and exile.8
To be clear, peace did not always or necessarily mean the absence of contention and violence. Peace meant coercion and war deployed in the right directions, for the right purposes, by the right authorities for the common good. In Lombardy, the Holy Land, and even the city of Rome, the pope and emperor confronted signs of the devil’s work, disturbers of the peace, warmongers, and sowers of scandal. As the head of the Roman church, Gregory possessed a compelling mandate for proclaiming peace, but he did not enjoy a monopoly over its creation. Papal and imperial networks of peacemaking ran on overlapping but sometimes divergent tracks. In different localities, the two Christian authorities confronted individuals and communities who refused their visions of peace or sought peace on different terms. Facing fluid political landscapes, Gregory and Frederick competed as much as cooperated, pursuing complementary but not identical ends, more often than not publicly rebuking each other for failing to live up to their divinely ordained duties. Rather than relieving the tensions embedded in the relationship between the two powers, reforming the peace transposed them into a different register.
Scars of War
Although the Treaty of San Germano had formally ended the fighting between the church and the prince, the process of turning that agreement into a meaningful political settlement on the Italian peninsula had just begun. By reconciling with Frederick, the pope shared public responsibility for the ruler’s subsequent actions. As early as October, Gregory warned him about certain men around Foggia conspiring to destroy the new peace, “murmuring” and “clamoring” that the convergence of two great lights—that of the pope and emperor—was casting them into the shadows. Such accusations caused him “grief in private, shame out in the open.” To prevent further blasphemy about “both our names,” Gregory called upon the emperor to act with mercy and forbearance, rather than giving such critics further reason to reproach the pope for the faith that he placed in Frederick. Judging by a letter sent to Frederick on 3 December, Gregory remained watchful for any signs of noncompliance on the emperor’s part. An envoy from the imperial court, a judge from Pavia identified only as G., had recently come to the papal curia with imperial “letters of security,” the promises sworn by various magnates and prelates to ensure that Frederick observed the terms established at San Germano. When the pope inspected the letters, however, he discovered several things omitted, either out of negligence or oversight. As a consequence, he decided not to “publicize” them, since this might give their detractors cause to “murmur” against them both. Gregory informed Frederick that he was sending Jacob, archbishop of Capua, to the imperial court to collate a complete dossier of the necessary documents. He also asked the emperor to recall the judge in question, who had continued on the road to Germany with the imperfect versions of the fiduciary letters, despite the pope’s instructions to suspend his journey.9
The War of the Keys had left the militarized Papal States and Regno in a disturbed condition. Not everyone was willing to lay down their arms and make the concessions demanded of them. The duchy of Spoleto remained a particular sore spot. The pope had appointed the bishop of Beauvais as its new duke, rewarding him for his service during the recent hostilities. When some of the locals rejected his lordship, he had to enter the duchy with an armed force.10 Frederick faced his own troubles trying to pacify the war-torn region. Richard of San Germano records that the emperor revoked his followers’ right to construct new fortifications, as permitted during the recent discord between church and empire. Gaeta remained another problem, since the fortified city refused to submit to the emperor’s authority as stipulated in the Treaty of San Germano, despite Gregory’s intervention on his behalf. This tense situation would last for years, until the commune finally acknowledged Frederick’s lordship and swore fealty to his young son Conrad, born from his marriage to Isabella of Brienne. Frederick also demanded restitution for damages caused during the recent war at Città di Castellana, although the pope reminded him that the commune pertained by right to the Apostolic See, as made evident by “many public charters.”11
More than anything else, however, the unresolved contention between the Lombard League and the emperor remained the true test of Gregory and Frederick’s willingness, commitment, and ability to reform the peace. The underlying sources of tension between the two sides, such as the extent of the emperor’s rights to appoint officials, dispense justice, collect tolls, and requisition supplies, remained unresolved. The fact that the “rebellious” Lombards had fought against him in the War of the Keys did not help matters. Gregory clearly viewed the stability of the region as critical to the new peace. In October 1230, when the pope informed the league’s rectors about Frederick’s reconciliation with the church, he had taken care to assure them about his ongoing support of their interests. He also forwarded to them some copies of the oaths sworn at San Germano by Thomas of Acerra on Frederick’s behalf, which bound the emperor to forgive the Lombards and other supporters of the church and to revoke all judgments, edicts, and bans issued against them. The possibilities for renewed contention between Frederick and the league never seemed far away, compelling Gregory to warn the emperor about moving against the Lombards “by the power of strength rather than the rule of law.”12
Positioning himself as the mediator for peace in the region, the pope did not unilaterally intervene on the Lombard League’s behalf. In September 1231, Frederick announced his intention to hold an assembly at Ravenna the upcoming November intended “to reform the universal peace of the empire, put Italy into a prosperous and tranquil state, and settle the fervid disputes inside and outside of its cities, removing the foment of hatred and every disturbance among neighboring peoples.” In the summons to the gathering, he stressed the fact that he proceeded by the counsel of the highest pontiff, a public sign of cooperation between church and empire for establishing peace