[4] After this Grellan proceeded to the upper third of Connacht and continued to traverse the country but he eventually settled and established a church at Cill Cluaine (or Kilclooney, near present-day Ballinasloe) in Magh Seincheineoil, a territory occupied by the Firbolg and led by Cian d'Fhearaibh Bolg.

Legend states that he prayed to God, who caused the Firbolgs to be swallowed into the earth at the bog of Magh Liach during battle with the Gaels.

The following year Thomas O'Curry arrived in the bally per the Ordnance Survey to learn that the Crozier of St. Ġreallán had been condemned and discarded.

Crannelly's kin had inherited the staff; attended church; heard Father O'Connor's sermon against their family for charging fees to swear oaths on the Baċall; after which the treasure disappeared.

Egan concludes the mystery thus "a treasured relic from the dawn of Christianity in Ireland, though handed down with loving care through thirteen centuries, was in the end put to base use, before finally disappearing from sight, perhaps forever.

The local branch of Conradh na Gaeilge (The Gaelic League) is named Craobh Ghrealláin in honour of the saint.