The Edict of Milan legalized the religion in 313, eroding traditional Roman values. It caused the Romans to move away from their belief in the emperor as a divine being and their enthusiasm for warfare. As a result, their military was weakened.
Popes and church leaders became more involved in politics, which complicated the government even further.
The Western Empire finally fell in the fifth century due to attacks from the Goths and the Huns. The Eastern Empire persisted until the 15th century. Eventually, it collapsed in a similar manner to its western counterpart.
