By 258 â `` 260 , the Empire split into three competing states , with the Gallic Empire including the Roman provinces of Gaul , Britannia and Hispania ; and the Palmyrene Empire , including the eastern provinces of Syria Palaestina and Aegyptus ; becoming independent from the Italian-centered Roman Empire proper between them . By 258 â `` 260 , the Empire split into three competing states : the Gallic Empire , including the Roman provinces of Gaul , Britannia and Hispania ; the Palmyrene Empire , including the eastern provinces of Syria Palaestina and Aegyptus ; and the Italian-centered and independent Roman Empire , proper , between them .