 In theory , the Roman Empire was not divided by the dual imperium . Though divisions did take place – each emperor had his own court , army , and official residences – these were matters of practicality , not substance . Imperial propaganda from 287 on insists on a singular and indivisible Rome , a patrimonium indivisum . As the panegyrist of 289 declares to Maximian : " So it is that this great empire is a communal possession for both of you , without any discord , nor would we endure there to be any dispute between you , but plainly you hold the state in equal measure as once those two Heracleidae , the Spartan Kings , had done . " Legal rulings were given and imperial celebrations took place in both emperors ' names , and the same coins were issued in both parts of the empire . Diocletian sometimes issued commands to Maximian 's province of Africa ; Maximian could presumably have done the same for Diocletian 's territory . 
