History of the East–West Schism
Disunion in the Roman Empire further contributed to disunion in the Church. The Emperor Diocletian famously divided the administration of the eastern and western portions of the Empire in the early 4th century, though subsequent leaders (including Constantine) aspired to and sometimes gained control of both regions. Theodosius the Great, who established Nicene Christianity as the official religion of the Roman Empire (see Edict of Thessalonica), was the last Emperor to rule over a united Roman Empire. Following his death in 395, the division into western and eastern halves, each for a few decades still under its own Emperor, was never reunited.
Roman triumph
For triumphs of the Roman regal era, the surviving Imperial "Fasti Triumphales" are incomplete. After three entries for the city's legendary founder Romulus, eleven lines of the list are missing. Next in sequence are Ancus Marcius, Tarquinius Priscus, Servius Tullius, and finally Tarquin "the proud", the last king. The "Fasti" were compiled some five centuries after the regal era, and probably represent an approved, official version of several different historical traditions. Likewise, the earliest surviving written histories of the regal era, written some centuries after it, attempt to reconcile various traditions, or else debate their merits. Dionysus, for example, gives Romulus three triumphs, the same number given in the "Fasti". Livy gives him none, and credits him instead with the first spolia opima, in which the arms and armour were stripped off a defeated foe, then dedicated to Jupiter. Plutarch gives him one, complete with chariot. Tarquin has two triumphs in the "Fasti" but none in Dionysius. No ancient source gives a triumph to Romulus' successor, the peaceful king Numa.