The Celtic incursions between the late 4th Century B.C. and the early decades of the 3rd Century B.C. into Greece and the Balkan Peninsula, are part of a series of geopolitical and military movements, well documented in Greek sources and confirmed by archaeological findings. The emergence of the Roman power, forced the Celtic population to find new territories to plunder which were weaker and vulnerable than those in Italy. Alexander the Great in 335 B.C., during his successful campaigns against the Triballians and the Paeonians, met some Celtic emissaries at the confluence of the Danube and the Morava, who exchanged gifts and hospitality. A second meeting would take place in 324 B.C. in Babylon. The subsequent Celtic incursions favoured the disorder which followed after the death of Alexander and the peace between the Romans and the Senones who were interested in the Greek Peninsula. A first wave of migration took place in 310 B.C., followed by another in 298 B.C. but it was after 281 B.C. with the death of Lysimachus of Thrace, in the battle of Curupedio which began the most massive and a:: essive incursion of Celtic people. In 2:1 B.C., imposing Celtic armies pushed through three routes into central Greece. They invaded Thrace and Macedonia, while Brennus and Akichorio with over 65,000 men, moved to Delphi, attracted by the enormous treasures that were kept in the sanctuary. Brennus, arrived at the Temple of Apollo which he desecrated. Then the Celts, still drunk from the wine they drank the night before, went into battle, but soon after, they were alarmed by earthquakes, landslides, thunder and lightning, which they recognized as signs of Apollo's intervention. They failed to win due to the renewed strength of the defenders and were forced to withdraw, without being able to plunder the temple (contrary to at is described by Roman sources). The waiver of Brennus, and heavy losses, caused the folding and dispersion of the army: the same Brennus was wounded and, at Heraclea, he enlisted the coup de grace. In 278 B.C., the remaining armies moved from Thrace to Asia Minor following an invitation by Mithridates II and Nicomedes of Bithynia who hired them as mercenaries in the dynastic struggle. While in the pay of Mithridates, they were victorious against Ptolemy, during the first Syrian war. Since then, many Greek, Egyptian, Carthaginian and Roman sovereigns used them as mercenaries.