They faced further reverses on the battlefield and a bitter guerrilla war in the Bosnian mountains, but bitter fighting also occurred in southern Pannonia around Mons Almus (modern Fruška Gora) near Sirmium. It took them three years of hard fighting to quell the revolt, which was described by the Roman historian Suetonius as the most difficult conflict faced by Rome since the Punic Wars two centuries earlier. Tiberius finally quelled the revolt in AD 9. This was just in time: that same year Arminius destroyed Varus's three legions in Germany. The Roman high command did not doubt that Arminius would have formed a grand alliance with the Illyrians.