The Romans had just defeated the Seleucids in the Roman-Syrian War and had forced them to thereby sue for peace. Following their recently successful operation in Syria, the Romans then turned their attention towards the Gallic tribes of Galatia who had emigrated to Asia Minor almost 100 years prior to the ensuing military engagement. Gnaeus Manlius Vulso, the consul, excused the invasion by saying that it was in retaliation for the Galatians supplying troops to the Seleucids during the war. Vulso embarked on this campaign without the permission of the Roman Senate. Joined by Pergamum, the Romans marched inland and attacked the Galatians. They defeated the Galatians in a battle on Mount Olympus and followed up the victory by defeating a larger army near Ankara.