In 1147, the Byzantine empire under Manuel I Comnenus is faced with war by Roger II of Sicily, whose fleet has captured the Byzantine island of Corfu and plundered Thebes and Corinth.

However, despite being distracted by a Cuman attack in the Balkans, in 1148 Manuel enlists the alliance of Conrad III of Germany, and the help of the Venetians, who quickly defeat Roger with their powerful fleet.

In 1149, Manuel recovers Corfu and prepares to take the offensive against the Normans, while Roger II sends George of Antioch with a fleet of 40 ships to pillage Constantinople's suburbs.

Manuel had already agreed with Conrad on a joint invasion and partition of southern Italy and Sicily.

The renewal of the German alliance remains the principal orientation of Manuel's foreign policy for the rest of his reign, despite the gradual divergence of interests between the two empires after Conrad's death.