Complex sentence: His father, Cennétig mac Lorcáin of Tuaith Muin (Thomond), king of the northernmost of the three principalities of Munster (died 951), was one of the principal leaders of the resistance to the Danish Viking incursions.
Split into simpler sentences: His father, Cennétig mac Lorcáin of Tuaith Muin (Thomond), was a king of the northernmost of the three principalities of Munster. Cennétig (died 951) was one of the principal leaders of the resistance to the Danish Viking incursions.