247-249 AD Ancient Rome Philip II Silver Antoninianus Ancient Grades xf. Philip II, also known as Philip the Younger, was the son and heir of the Roman emperor Philip the Arab by his wife Marcia Otacilia Severa. Ancient historians say that Philip the Arab and Philip II were both killed in battle by Decius in 249. Modern historians say that when news of Philip the Arab's death reached Rome, Philip II was murdered by the Praetorian Guard at the age of twelve. Some argue that Philip II was sole ruler of the empire for the fall of 249.