Following their successful conquest of southern Italy, the Normans see no reason to stop; Byzantium is decaying further still and looks ripe for conquest.

When Alexios I Komnenus ascends to the throne of Byzantium, his early emergency reforms, such as requisitioning Church money -- a previously unthinkable move -- prove too little to stop the Normans.Led by the formidable Robert Guiscard and his son Bohemund, they take Dyrrhachium and Corfu, and lay siege to Larissa in Thessaly (see Battle of Dyrrhachium).

Alexios suffers several defeats before being able to strike back with success.

He enhances this by bribing the German king Henry IV with 360,000 gold pieces to attack the Normans in Italy, which forces the Normans to concentrate on their defenses at home in 1083–1084.

He also secures the alliance of Henry, Count of Monte Sant'Angelo, who controls the Gargano Peninsula and dates his charters by Alexios' reign.

Henry's allegiance is to be the last example of Byzantine political control on peninsular Italy.

The Norman danger ends for the time being with the death of Robert Guiscard in 1085, combined with a Byzantine victory and crucial Venetian aid, allows the Byzantines to retake the Balkans.