His palace eventually became the core of the modern-day city of Split in Croatia.Diocles' parents were of low status, and writers critical of him claimed that his father was a scribe or a freedman of the senator Anullinus, or even that Diocles was a freedman himself.The army unanimously saluted Diocles as their new augustus, and he accepted the purple imperial vestments.He raised his sword to the light of the sun and swore an oath disclaiming responsibility for Numerian's death.
Carinus quickly made his way to Rome from his post in Gaul as imperial commissioner and arrived there by January 284, becoming legitimate Emperor in the West. The Sassanid king Bahram II could not field an army against them as he was still struggling to establish his authority.
By March 284, Numerian had only reached Emesa (Homs) in Syria; by November, only Asia Minor.
On 20 November 284, the army of the east gathered on a hill 5 kilometres (3.1 mi) outside Nicomedia.
Bureaucratic and military growth, constant campaigning, and construction projects increased the state's expenditures and necessitated a comprehensive tax reform.
From at least 297 on, imperial taxation was standardized, made more equitable, and levied at generally higher rates.