His policy succeeded for a time, but following his abdication in a.d. 305, the empire continued to weaken, harassed by invaders and troubled by internal strife.
His abdication took place in 500 A.D. 
mnli hypothesis: His abdication took place in 500 A.D.  premise: His policy succeeded for a time, but following his abdication in a.d. 305, the empire continued to weaken, harassed by invaders and troubled by internal strife.