take a letter to the emperor outlining Lothair’s attacks on the Church, which they managed to get past Lothair’s troops at Bologna. Then in 840, with Louis’ death and the accession of Lothair as emperor, war again erupted between the sons of Louis. Gregory made unsuccessful attempts to mediate in the conflict that ensued between the brothers, sending Archbishop George of Ravenna as his representative. According to Prudentius of Troyes, George faithfully tried to achieve his objective, but failed due to Lothair’s refusal to allow George to see Lothair’s brothers. However, according to Andreas Agnellus, George tried to bribe Lothair to make his archbishopric independent of Rome, and was captured at the Battle of Fontenoy. The subsequent Treaty of Verdun in 843 broke up the empire of Charlemagne, with Lothair retaining the imperial title and control of Italy. Building activities and religious issues Gregory repaired the Aqua Traiana, which had been damaged during the pontificate of Leo III. Sometime after 841 Gregory rebuilt and fortified parts of the port of Ostia against the attacks of Saracens, renaming it Gregoriopolis. Around the same time he restored the colony of Galeria along the Via Portuensis, while also establishing a new colony, called Draco, along the left bank of the Tiber River, some eleven miles from Rome along the Via Ostiensis. This was the first clear example of land development undertaken by a pope within his own territory. Gregory contributed to the architectural development of Rome. In 833, Gregory completely rebuilt St Mark’s Basilica in Rome, adorning the walls with Byzantine-style mosaics, as well as a number of other churches which he either repaired or rebuilt. He rebuilt the atrium of St. Peter’s Basilica, and within the newly decorated chapel within the basilica he transferred the body of Saint Gregory, and from the Catacombs of Rome, he moved Saint Sebastian, Saint Tiburtius, and Saint Gorgonius. He raised the altar in the church of Santa Maria in Trastevere, and founded a monastery close to the church. Gregory’s pontificate witnessed the end of the iconoclasm controversy in the Byzantine Empire, while Gregory himself promoted the celebration of the feast of All Saints within the Frankish kingdom on both sides of the Rhine River. Gregory is also known for his appointment of Ansgar as archbishop of Hamburg-Bremen in 832, and as the apostolic legate to the northern and eastern parts of Europe. On 31 March 837