Missionary in Ireland, assigned by Saint Patrick to build a church at Achadh Fionnabhrach; king Duach Gallach gave Grellan land for the church after Grellan brought back to life by baptism Duach Gallach’s stillborn son, Eoghan Sriabh.
- “Saint Grellen“. CatholicSaints.Info. 7 November 2015. Web. 31 March 2017. <>