The siege of Philippopolis was fought in about 250 between Rome and the Goths during the invasions of 249–253 at the Thracian city of Philippopolis, modern Plovdiv, Bulgaria. It was part of the long-running series of Gothic Wars. The Goths were led by King Cniva who had crossed the Danube in 249 or 250 with two armies. His army attacked Novae and Nicopolis ad Istrum unsuccessfully before defeating the army of Emperor Decius at Augusta Traiana and moving on to Philippopolis. Decius had been on his way to relieve Philippopolis with a reinforced army, but arrived too late.