316 - 326 A.D.
Crispus was the oldest son of Constantine. He was made Caesar in about
316 and groomed along the military and political ways to be expected of a
future emperor. However, his career was cut short in 326 when his
stepmother Fausta accused him of attempted rape. Her story must have
sounded like an unspeakable atrocity for Constantine had his son put to
death at once. Some time later it was somehow found out that she'd made up
the entire story and Constantine had her literally boiled to death.
Fausta's motive most likely had to do with removing Crispus from the line
of succession to make way for her own sons. This much she was successful
at since they did indeed become emperors some ten years afterwards.