60/59BC he defeated and conquered the Boii, who were led by Critasiros, and the Taurisci tribes dwelling in the Middle Danube, in modern Bohemia and Slovakia. The Boii had established a tribal presence in the areas now occupied by eastern Austria and south-western Slovakia and Hungary sometime in 75–50BC. The Boii extended their influence eastward towards modern day Bratislava, Slovakia around 64–63BC. It is these Boii tribes east of the Alps that came into conflict with the Dacians and were heavily defeated in 50–40BC. These conquests were followed by the destruction of the Bastarnae peoples. Similarly, Burebista conquered a tribe that Strabo describes as living among the Illyrians and Thraciansmost likely the Scordisciwhile simultaneously conducting raids throughout Thrace, Roman Macedonia, and Illyria. Capture of Greek cities Beginning around 55 BC Burebista annexed the Greek cities on the coast of the Black Sea, occupying the Greek fortresses from Olbia to Apollonia, as well as the Danubian plain all the way to the Balkans. These conquered cities were: Olbia, Tyras, Histria, Tomis, Callatis, Odessos, Messembria, Apollonia, and Dionysopolis. Dionysopolis, however, enjoyed good relations with Burebista. An inscription dating to 48BC found in Dionysopolis and in honour of Akornion of Dionysopolis describes Akornion as the "first and greatest friend" of Burebista. Akornion was sent as an ambassador to Pompey to claim the title of "king of kings" for Burebista to be used within the Hellenistic kingdoms of the Balkans and the Near East. Caesar's civil war Burebista inevitably came into conflict with Rome. During the Roman civil war of 49–44 BC, Pompey gained the support of Burebista through Akornion of Dionysopolis. Pompey himself had recognized might of Burebista and Dacia after their successful conquests against the Greek Black Sea cities. Caesar, however, ended any alliance between Pompey and Burebista at the Battle of Pharsalus. Caesar was also aware of the growing strength of the Dacians and had planned to lead an attack against Burebista. Burebista at this time had a force that may have numbered up to 200,000 menthough it is disputed whether this force was an actual military force or the number of ablebodied men within the kingdom. Regardless, Dacia was a formidable power that Caesar perceived as a threat to Rome. But Caesar was never able to start his intended campaign because he was assassinated in 44BC, Burebista meeting the same fate when he was killed in a civil uprising in