<P> Around 300 AD, the Emperor Diocletian enacted a series of constitutional reforms . In one such reform, Diocletian asserted the right of the Emperor to take power without the theoretical consent of the Senate, thus depriving the Senate of its status as the ultimate depository of supreme power . Diocletian's reforms also ended whatever illusion had remained that the Senate had independent legislative, judicial, or electoral powers . The Senate did, however, retain its legislative powers over public games in Rome, and over the senatorial order . The Senate also retained the power to try treason cases, and to elect some magistrates, but only with the permission of the Emperor . In the final years of the Empire, the Senate would sometimes try to appoint their own emperor, such as in case of Eugenius who was later defeated by forces loyal to Theodosius I . The Senate remained the last stronghold of the traditional Roman religion in the face of the spreading Christianity, and several times attempted to facilitate the return of the Altar of Victory, first removed by Constantius II, to the senatorial curia . </P> <P> After the fall of the Western Roman Empire, the Senate continued to function under the barbarian chieftain Odoacer, and then under Theoderic the Great who founded the Ostrogothic Kingdom . The authority of the Senate rose considerably under barbarian leaders who sought to protect the institution . This period was characterized by the rise of prominent Roman senatorial families such as the Anicii, while the Senate's leader, the princeps senatus, often served as the right hand of the barbarian leader . It is known that the Senate installed Laurentius as antipope in 498 despite the fact that both King Theodoric and Emperor Anastasius supported Pope Symmachus . </P> <P> The peaceful co-existence of senatorial and barbarian rule continued until the Ostrogothic leader Theodahad began an uprising against Emperor Justinian I and took the senators as hostages . Several senators were executed in 552 as a revenge for the death of the Ostrogothic king Totila . After Rome was recaptured by the Imperial (Byzantine) army, the Senate was restored, but the institution (like classical Rome itself) had been mortally weakened by the long war between the Byzantines and the Ostrogoths . Many senators had been killed and many of those who had fled to the East chose to remain there thanks to favorable legislation passed by emperor Justinian, who however abolished virtually all senatorial offices in Italy . The importance of the Roman Senate thus declined rapidly . In 578 and again in 580, the Senate sent envoys to Constantinople who delivered 3000 pounds of gold as a gift to the new emperor Tiberius II Constantinus along with a plea for help against the Langobards who had invaded Italy ten years earlier . Pope Gregory I, in a sermon from 593 (Senatus deest, or. 18), lamented the almost complete disappearance of the senatorial order and the decline of the prestigious institution . It is not clearly known when the Roman Senate disappeared in the West, but it is known from Gregorian register that the Senate acclaimed new statues of Emperor Phocas and Empress Leontia in 603 . The institution must have vanished by 630 when the Curia was transformed into a church by Pope Honorius I . The Senate did continue to exist in the Eastern Roman Empire's capital Constantinople, however, having been instituted there during the reign of Constantine I . The Byzantine Senate survived until at least the mid-14th century, before the ancient institution finally vanished from history . </P>

Who took power by disobeying the roman senate