A timeline started by jmberry in spring 2009 and updated sporadically since. The timeline is somewhat less in depth than his other timeline, The Two Unlucky Soldiers, due to the longer period of time End of an Age takes place. Note that the link below leads to the thread's beginning, which was an older, discarded version of the timeline. The current timeline doesn't start until Post #14.
The Point of Divergence is the Battle of Naissus in 268. There is some debate as to who was emperor at the time, but for the purposes of the timeline it is assumed Gallienus was emperor. OTL Gallienus won the battle, then hastened to Milan, where he was assassinated, leading to Claudius II becoming emperor and beginning the process that saw the reunification of the Roman Empire under Aurelian. ITTL, the Goths win, and Gallienus and Aurelian are killed. Claudius still declares himself emperor, but the usurper Aureleos is able to use the defeat to confirm his hold on the Imperial throne, leading the Empire to break apart even further. With no one man able to reunify the empire, Postumus' Gallic Empire and Zenobia's Palmyrene Empire are able to cement their independence.
As of the time of writing, the timeline is at 400 and several nations exist where once there was one:
Roman Empire of Gaul
Founded by Postumus before the POD, the Roman Empire of Gaul contains Gaul and Britain. Initially ruled by the Postumus, it was soon taken over by Victorinus I, who declared the Sol Invictine faith to be the state religion. Victorinus' family ruled for several generations, until they themselves were overthrown by Afranius. Afranius' descendent Silvanus currently rules the empire.
Principate of Hispania
The Principate of Hispania was recently founded by Quintus Cassius Victorinus of the Cassii Family. They splintered from the Gallic Empire. Like Gaul, they follow the Sol Invictine faith.
Restored Roman Empire
The Restored Roman Empire is the spiritual successor to the original Roman Empire. Founded by Julius Saturninus as the African Empire, it was initially in opposition to to the empire based in Italy. Later, Italy became a vassal of the Gallic Empire, under a younger son of Victorinus II. The Paivonines, as they were called, ruled decently for several decades, but Saturninus's successors ultimately returned to Italy and drove them out. Aurelius Ambrosius, the son of a Gallo-Roman who defected to the Africans, is the current Emperor. The Restored Empire, like the African Empire it grew out of, is Christian.
The Palmyrene Empire was founded by Odenaethus of Tadmor, a loyal subject of Rome. When he died, his wife Zenobia decided that Palmyra would do better as an independent kingdom, and declared independence. When their son Vaballathus Athenodorus came of age, he had Zenobia removed and maintained Palmyra's independence. His son Odenaethus II converted to Christianity, and so Palmyra has been the center of Christian culture ever since.
Gothia is a young nation founded by the Ostrogoths on the ruins of the Illyrian based empire and its Anatolian splinter. They are largely Manichaean, like the Asian Empire they conquered, though there is a largely Marcionitic population in Macedonia, descended from the Visigoths.
Rafidayn is an Arab kingdom in Mesopotamia (indeed, Rafidayn is simply Arabic for Mesopotamia) founded by the Lakhmids. Rafidayn is a Christian country based in Al-Hira, who are best known for being a thorn in the side of Persia.
And several Germanic and Slavic tribes in the Balkans.