Complex sentence: The Battle of Belach Lechta or Bealach Leachta was an important battle fought in 978 in Munster between Máel Muad mac Brain, King of Munster, and Brian Bóruma, younger brother of Mathgamain mac Cennétig and future High King of Ireland.
Split into simpler sentences: The Battle of Belach Lechta or Bealach Leachta was an important battle fought in 978 in Munster between Máel Muad mac Brain, King of Munster, and Brian Bóruma. Bóruma was the younger brother of Mathgamain mac Cennétig and in line to be the next High King of Ireland.