Answer the question from the given passage. Your answer should be directly extracted from the passage, and it should be a single entity, name, or number, not a sentence.
Q: Passage: Soon after the Normans began to enter Italy, they entered the Byzantine Empire and then Armenia, fighting against the Pechenegs, the Bulgars, and especially the Seljuk Turks. Norman mercenaries were first encouraged to come to the south by the Lombards to act against the Byzantines, but they soon fought in Byzantine service in Sicily. They were prominent alongside Varangian and Lombard contingents in the Sicilian campaign of George Maniaces in 1038–40. There is debate whether the Normans in Greek service actually were from Norman Italy, and it now seems likely only a few came from there. It is also unknown how many of the 'Franks', as the Byzantines called them, were Normans and not other Frenchmen. Question: Who was the Normans' main enemy in Italy, the Byzantine Empire and Armenia?
A:
Seljuk Turks