Expeditions in the Mediterranean region and Africa

In addition to the unification of Italy, Roger dreamed of a Norman Mediterranean. He started with an intervention in Ifriqiya (present day Tunisia), where anarchy prevailed at this time. Several attempts were made to seize Mahdia, between 1117 and 1123. The failure of his campaign harmed the myth of Norman invincibility and led to an increase in the incursions of Muslim pirates in Sicily.
From 1128, Roger undertook a privateering war. Djerba was taken in 1134, offering a base for Norman corsairs in the western Mediterranean; from 1144 this was strengthened by other possessions on the coast. In 1146, Tripoli (Cyrenaique), capital of Arab privateering was seized, and, in 1147, Gabes, Sfax, Sousse and then Mahdia. The North African coast was more or less under a mild tutelage, paying tribute to the conqueror, but keeping its customs and structures. Bone (Algeria) was taken in 1153, but the conquest came to an end and acquisitions gained were gradually lost, when eventually in 1160, the Normans were expelled by the Almohades who were making headway in North Africa.
At the same time, Roger led an equally aggressive policy to the East. Excluded by Manuel I Comnenus and Conrad III from participating in the Second Crusade, he decided, in 1147, to destabilise the basileus. In 1147 and 1148, he took different towns and islands in the Adriatic, notably Corfu, the central point of Byzantine trade, and literally pillaged Greece and its coastline. Roger scorched Athens, razed Thebes, the silk production centre of the eastern Mediterranean, taking back an enormous booty.
In 1148, the basileus allied with the Venetians and concluded an entente with the German emperor envisaging the invasion and sharing out of the Norman kingdom: Calabria and Apulia for the first and the rest for the second. Roger ransacked the port of Byzantium in 1149, and, allied with the Guelphs (the Italian faction hostile to the German emperor), forced Conrad III to sign a peace treaty. In 1151, the basileus undertook once more its coalition project with Conrad III and this time with the maritime power of Pisa. But the invasion was abandoned in 1152.