Pelagius' Hip Bone is an item acquired from Dervenin when the quest "The Mind of Madness" is accepted. The bone appears to be the pelvis of Pelagius the Mad, one of the previous Emperors of the Septim Dynasty.
According to Dervenin, the bone is essential to gaining access to Sheogorath's realm, hidden within the Pelagius Wing of the Blue Palace. The item is still kept after the quest is completed, and can be sold to merchants, or simply used as decoration.
Dervenin will give the Dragonborn the hip bone when spoken to.
- The pelvis, when dropped, is incredibly small; it appears to be roughly the same size as a hand.