Severus Alexander was the last emperor from the Severan Dynasty started by Septimius Severus in 193 AD. Due to his age, his mother, Julia Mamaea served as his regent and was instrumental in his reign. In fact, Severus Alexander died along with his mother when the Praetorian Guard murdered them both and threw their bodies in the Tiber. His death set off a series of men vying for the throne. This period was known as the Crisis of the Third Century, a fifty year period of civil unrest, numerous short-term rulers and economic instability.