He established new administrative centres in Nicomedia, Mediolanum, Sirmium, and Trevorum, closer to the empire's frontiers than the traditional capital at Rome. Diocletian led the subsequent negotiations and achieved a lasting and favourable peace.Дiocletian separated and enlarged the empire's civil and military services and reorganized the empire's provincial divisions, establishing the largest and most bureaucratic government in the history of the empire.

In 299 he sacked their capital, Ctesiphon. Galerius, aided by Diocletian, campaigned successfully against Sassanid Persia, the empire's traditional enemy. He defeated the Sarmatians and Carpi during several campaigns between 285 and 299, the Alamanni in 288, and usurpers in Egypt between 297 and 298. Diocletian secured the empire's borders and purged it of all threats to his power. Under the Tetrarchy, or 'rule of four', each emperor would rule over a quarter-division of the empire.

Diocletian delegated further on 1 March 293, appointing Galerius and Constantius as junior co-emperors (each with the title Caesar), under himself and Maximian respectively. Diocletian reigned in the Eastern Empire, and Maximian reigned in the Western Empire. He appointed fellow officer Maximian as Augustus, co-emperor, in 286. The title was also claimed by Carus's surviving son, Carinus, but Diocletian defeated him in the Battle of the Margus.Дiocletian's reign stabilized the empire and marks the end of the Crisis of the Third Century. After the deaths of Carus and his son Numerian on campaign in Persia, Diocletian was proclaimed emperor. Born to a family of low status in Dalmatia, Diocletian rose through the ranks of the military to become a cavalry commander of the Emperor Carus's army. 244 вЂ“ 3 December 311) was a Roman emperor from 284 to 305.

Й™ Л€ k l iЛђ Кѓ Й™n/ Latin: Gaius Aurelius Valerius Diocletianus born Diocles 22 December c.

Diocletian war of all against all