Olenveld once had a large bustling city, but it was later abandoned sometime in the Second Era. Tiber Septim later used the island as a mass graveyard, covering the defunct streets in gravestones. In time, the island was forgotten by the populace, and its location no longer put on maps.
When Hannibal Traven became the Arch-Mage of the Mages Guild in 3E 431, he instituted a ban on Necromancy within the Guild. A group of necromancers then went into hiding, and set out on an expedition to find Olenveld due to its remote location and plentiful supply of corpses. After searching for around a week, they reached the forgotten city and set up their headquarters in the abandoned Mages Guild building. The group then became somewhat known due to their ability in "curing" ill children, by turning them undead in order to preserve their bodies.