On October 28, 312 AD Constantine and Maxentius fought a battle at Rome's doorstep for control of the Western Empire.

Prior to the Battle of the Milvian Bridge Constantine experienced visions and dreams that promised him victory if he embraced Christianity.

With the Tetrarchy in shambles, Diocletian will be called out of retirement in 308 AD to help broker a settlement. But the new new order will prove as bad as the old new order.

Less than two years after Diocletian's abdication, the Tetrarchy was left in shambles following the power plays of Constantine and Maxentius.

In 305 AD, Diocletian and Maximian voluntarily abdicated the throne, handing power over to Galerius and Constantius.

In 303 AD Diocletian initiated the last and greatest of the Christian persecutions.

Rome's economy was in disarray when Diocletian came to power and he initiated major overhauls to get the system running again.

Over the course of his reign Diocletian overhauled the government, transforming it into a centralized bureaucracy run by career civil servants.

Over the course of his reign Diocletian instituted a number of reforms to the military structure that helped transform the legions into a new kind of army.

In the mid-to-late 290s the Imperial Tetrarchy was at war on multiple fronts. In the west Constantius undertook the reconquest of Britain, while in the east, Galerius fought a newly hostile Sassanid Empire.