Tying directly into the previous chapter on Lothar I, this contribution looks at the earliest part of the rule of Louis II in Italy. Louis had been appointed sub-king of his father, Emperor Lothar I, in 840,by his grandfather Louis the Pious. In 844, he was sent on his first dpilomatic and military mission by his father, under the supervision of his uncle Drogo of Metz. This mission at the head of a sizeable army and group of bishops from Lothar's realm was destined to go to Rome and get Pope Sergius II in line, as he had been raised to the apostolic see without the emperor's consent. The expedition was then possibly also to go on to southern Italy and interfere in the ongoing civil war among the Beneventan Lomabards, but negotiations in Rome with the southern Prince Siconulf and Guy of Spoleto prevented that move at this point. The chapter thus shows the young king and future emperor Louis at the earliest stage of his carreer and how Lothar I paved the way for his oldest son to rule the kingdom assigned to him.

In the Basilica of St John Lateran in the Middle Ages there have been many building projects, some of considerable scale, which are nonetheless not easy to identify. This chapter focusses on two examples, both of which give important insights into the building techniques employed: the lost front porch built by Pope Sergius II (844-847), which surviving illustrations indicate employed Carolingian construction technique typical for Rome, and the transept with the two bell towers attached to the northern side of the Basilica. In this second case the material evidence indicates both date of the building, in all probability from the pontificate of Nicholas IV (1288-1292), and its fine quality, appropriate to the exceptional importance of the project.