* The Roman Empire before Constantine (306-337 AD) was ruled by a series of emperors. Constantine's rise to power was a complex one, and he shared the throne with others for a significant period. It's not simply a case of one person ruling before him.
* The emperors who ruled before Constantine were part of the Tetrarchy system. This system, established by Diocletian, divided the empire into four regions, each ruled by an "Augustus" and a "Caesar". Constantine's father, Constantius Chlorus, was one of these Augustuses.
* Constantine ultimately consolidated power after several years of conflict and political maneuvering. He defeated his rivals, including Maxentius and Licinius, and became the sole emperor of the Roman Empire.
Here are some of the major emperors who ruled before Constantine:
* Diocletian (284-305 AD), who established the Tetrarchy.
* Galerius (305-311 AD), who was Diocletian's successor.
* Constantius Chlorus (305-306 AD), Constantine's father, who was one of the four Augustuses.
* Maximian (286-305 AD), who was Diocletian's co-Augustus.
Therefore, pinpointing a single ruler "before Constantine" is inaccurate, as the Roman Empire was under various emperors during a complex period.