Complex sentence: Uí Enechglaiss was an early king of the region, who along with the Uí Failge and Uí Bairrche, belonged to the Laigin, but may also be associated with the Érainn.
Split into simpler sentences: Uí Enechglaiss was an early king of the region. They who along with the Uí Failge and Uí Bairrche, belonged to the Laigin, but may also be associated with the Érainn.