In March 1123, Calixtus II convened the First Lateran Council which passed several disciplinary decrees, such as those against simony and concubinage among the clergy, and violators of the Truce of God.

As archbishop, he was appointed papal legate to France by Pope Paschal II during the time that Paschal was induced under pressure from Holy Roman Emperor Henry V to issue the Privilegium of 1111, by which he yielded much of the papal prerogatives that had been so forcefully claimed by Pope Gregory VII in the Gregorian Reforms.

[4] On his return to France, he immediately convened an assembly of French and Burgundian bishops at Vienne, where the imperial claim to a traditional lay investiture of the clergy was denounced as heretical and a sentence of excommunication was now pronounced against Henry V on the grounds that he had extorted the Privilegium from Paschal II by means of violence.

[6][4] Paschal does not seem to have been quite pleased with Guy's zeal in his attacks upon Henry V.[4] During the violent confrontations between Henry V and Paschal II's successor, Pope Gelasius II, the pope was forced to flee from Rome, first to Gaeta, where he was crowned, then to the Cluny Abbey, where he died on 29 January 1119.

[4] At the outset, it appeared that the new pope was willing to negotiate with Henry V, who received the papal embassy at Strasbourg, and withdrew his support from the antipope he had proclaimed at Rome.

The Imperial candidate was obliged to flee to the fortress of Sutri, where he was taken prisoner through the intervention of Norman support from the Kingdom of Sicily.

[8] The bull forbade Christians, on pain of excommunication, from forcing Jews to convert, from harming them, from taking their property, from disturbing the celebration of their festivals, and from interfering with their cemeteries.

Henry V was anxious to put an end to a controversy which had reduced imperial authority in Germany — terminally so, as it appeared in the long run.

On his side the Emperor abandoned his claim to investiture with ring and crosier, and granted freedom of election to episcopal sees.

The indulgences already granted to the crusaders were renewed, and the jurisdiction of the bishops over the clergy, both secular and regular, was more clearly defined.

A decade or two later, a French scholar (probably Aymeric Picaud) began composing a combination of miracle tales, liturgical texts and travelers guide relating to the increasingly popular pilgrimage route from southern France through northern Spain now called the Camino de Santiago.

The work (published before 1173) was called the Liber Sant Jacobi (Book of St. James) or the Codex Calixtinus, since a letter introduction attributed to this pope preceded each of the five chapters.