fluvial fleet controlling the Upper Danube from Castra Regina in Raetia (modern Regensburg) to Singidunum in Moesia (modern Belgrade). Its exact date of establishment is unknown. Some trace it to Augustus' campaigns in Pannonia in ca. 35 BC, but it was certainly in existence by 45 AD. Its main base was probably Taurunum (modern Zemun) at the confluence of the river Sava with the Danube. Under the Flavian dynasty, it received the cognomen Flavia. The Classis Perinthia, established after the annexation of Thrace in 46 AD and based in Perinthus. Probably based on the indigenous navy, it operated in the Propontis and the Thracian coast. Probably united with the Classis Pontica at a later stage. The Classis Pontica, founded in 64 AD from the Pontic royal fleet,Starr (1989), p. 76 and based in Trapezus, although on occasion it was moved to Byzantium (in ca. 70), and in 170, to Cyzicus. This fleet was used to guard the southern and eastern Black Sea, and the entrance of the Bosporus. According to the historian Josephus, in the latter half of the 1st century, it numbered 40 warships and 3,000 men. The Classis Syriaca, established probably under Vespasian, and based in Seleucia Pieria (hence the alternative name Classis Seleucena) in Syria. This fleet controlled the Eastern Mediterranean and the Aegean sea. In addition, there is significant archaeological evidence for naval activity by certain legions, which in all likelihood operated their own squadrons: legio XXII Primigenia in the Upper Rhine and Main rivers, legio X Fretensis in the Jordan River and the Sea of Galilee, and several legionary squadrons in the Danube frontier. Dominate period Our main source for the structure of the late Roman military is the Notitia Dignitatum, which corresponds to the situation of the 390s for the Eastern Empire and the 420s for the Western Empire. Notable in the Notitia is the large number of smaller squadrons that have been created, most of these fluvial and of a local operational role. Fleets of the Danube frontier The Classis Pannonica and the Classis Moesica were broken up into several smaller squadrons, collectively termed Classis Histrica, authority of the frontier commanders (duces). with bases at Mursa in Pannonia II, Florentia in Pannonia Valeria, Arruntum in Pannonia I, Viminacium in Moesia I and Aegetae in Dacia ripensis. Smaller fleets are also attested on the tributaries of the Danube: the Classis Arlapensis et Maginensis (based