Papal legations
Otto undertook numerous missions for Gregory IX in northern Europe. In December 1227, he was sent with Cardinal Thomas of Capua on a secret mission to the Frederick II, Holy Roman Emperor. By January 1228, he was back in Rome. In February 1229, he left on a major legation to northern Europe that lasted until 1231. In April, he was at Paris assisting in the negotiations between the Queen Regent Blanche and Count Raymond VII of Toulouse that produced the Treaty of Paris (April 12).
Otto subsequently pursued ecclesiastical reforms in the Holy Roman Empire. In 1229, he issued statutes for the reform of the Benedictines and Augustinians in Alsace, and between December 1229 and May 1230 he helped organize a new religious order, the Penitent Sisters of Saint Mary Magdalene in Germany. In the summer of 1230, he visited Denmark and Norway. There he promulgated a statute forbidding clerical concubinage. From Denmark, he went to Bremen, then Munich, then Cologne, where he convoked a council of the German church to be held at Würzburg. He met resistance from the secular leaders and the council was poorly attended. According to the Royal Chronicle of Cologne, Otto "withdrew irate" (iratus recessit). He rejoined the Papal court at Rieti in early summer 1231.
Early in 1232, Gregory IX sent Otto with Cardinal James of Pecorara to northern Italy to negotiate a peace between the warring factions of the Guelphs and Ghibellines, the latter the allies of Emperor Frederick II. Frederick, however, caused negotiations to drag on for over a year before an agreement was reached.
Between 1233 and 1237, Otto was mostly with the Papal court, acting as auditor again. In May 1236, King Henry III of England requested a Papal legate be sent to his kingdom to resolve both internal disputes and a dispute with King Alexander II of Scotland. In August 1236, Gregory IX appointed Otto as legate a latere. He left on 13 April 1237, arriving in England in July. His remit covered not only England, but Scotland and Ireland also.
Otto presided over the negotiations between Henry III and Alexander II that began on 14 September 1237 and ended with the signing of the Treaty of York on 25 September. He then presided over the a council of the English church in London, which adopted reforms in line with the Fourth Lateran Council of 1215. The statutes promulgated by Otto after this council are transmitted in more than sixty manuscripts.
He mediated between the Archbishop of Canterbury and Archbishop of York in London in 1237. When in July 1237 he came to Osney Abbey, a brawl broke out between a group of scholars from the university and the cardinal's men in which the legate's cook was killed. Otto himself was locked for safety in the abbey tower, emerging unscathed to lay the city under interdict in reprisal. In 1240 he visited Shaftesbury Abbey and confirmed a charter of 1191, the first entered in the Glastonbury chartulary.
Otto resided in London throughout most of 1238 and 1239. On 10 November 1238, he attended a meeting of the provincial chapter of Benedictine abbots and priors. In 1239, he went to Scotland to publish the excommunication of the Emperor Frederick II. In October he held a council in Edinburgh to introduce the Lateran reforms to the Scottish church. He visited Ireland to do the same before returning to London, where he spent the next year. He left England on 29 December 1240.
