Emperor Alexius I Comnene

Alexius was the most capable of the Byzantine rulers in the late years of the empire. A victorious general in many battles, Alexius fought the Turks, Parthians, and Thracians as well as Byzantine rebels. His greatest military challenge would come after he assumed the Byzantine throne.
Alexius was designated emperor in 1081 subsequent a palace coup which deposed the inept Nicephorus III Botaneites. One of the first major issues facing the newly installed emperor was the need for reorganization and revitalization of the declining Byzantine army. At the same time, this army faced an invasion by the Normans under the fearsome Robert Guiscard, Duke of Apulia and his warrior son, Bohemond.
The Byzantines were faced with defeat at the hands of the Normans when typhoid broke out in the Norman army, taking among others the Duke of Apulia himself in 1085. The retiring Norman host gave Alexius time to repair his ever-shrinking empire. Alexius would meet Bohemond again when Bohemond entered Constantinople as one of the leaders of the First Crusade in 1097.