Hervé (Greek: Ἑρβέβιος, Ervevios, Italian: Erveo), called Frankopoulos or Phrangopoulos (Greek: Φραγγόπουλος, "Son of the Frank"), was a Norman mercenary general in Byzantine service during the 1050s.
According to Amatus of Montecassino, Hervé and other Norman mercenaries fought for the Byzantine Empire under George Maniakes against the Muslims in Sicily in 1038-1040. Between 1040 and 1043, he took part in the campaign against the Greeks of Apulia and received the city of Avellino (1042/3). At about 1050, he appears as the leader of the Norman mercenaries under Nikephoros Bryennios the Elder and one of the Greek's two chief lieutenants. In the same year, he and Katakalon Kekaumenos were defeated by the Pechenegs near the Danube.
In 1056, he demanded the high court title of magistros from Emperor Michael VI Stratiotikos (r. 1056–1057). Refused, he withdrew to his estate in the Armeniac theme. From there, he gathered a following of 300 Normans, and in spring 1057 he marched into eastern Asia Minor, around Lake Van. There, he possibly aimed to set up a state for himself, and entered into wars with the Armenians and the Seljuk Turks. After initial success, he was eventually captured by a ruse by the emir of Ahlat, Abu Nasr.
Hervé was shipped back to Constantinople in chains, but there he was apparently reconciled to the Byzantine emperor: a surviving seal records his having received the title of magistros, and the positions of vestiarites and stratelates of the East in the army of Emperor Isaac I Komnenos (r. 1057–1059). In circa 1063, however, Matthew of Edessa records that the Turks of Amida bribed a certain "Frankabol", to avoid battle. Whether this was indeed Hervé is uncertain, but he was executed by Emperor Constantine X Doukas (r. 1059–1067) shortly after. He was possibly the founder of the late Byzantine Phrangopoulos family.
- Gravett, Christopher; Nicolle, David (2006). The Normans: Warrior Knights and their Castles. Oxford, United Kingdom: Osprey Publishing Limited. ISBN 1-84603-218-0.
- Kazhdan, Alexander Petrovich, ed. (1991). Oxford Dictionary of Byzantium. New York, New York and Oxford, United Kingdom: Oxford University Press. ISBN 978-0-19-504652-6.
- Schlumberger, Gustave (1881). "Deux Chefs Normands des Armées Byzantines au XI Siècle: Sceaux de Herve et de Raoul de Bailleul". Revue Historique (Paris, France) (16): 289–303.