Complex sentence: Upon the death of a chief, the succession was hereditary starting with the eldest son and so on, in case there were no sons available, the closest male family member was chosen by the counsel of elders and priests.
Split into simpler sentences: Upon the death of a chief, the succession was hereditary starting with the eldest son and so on. In case there were no sons available, the closest male family member was chosen by the counsel of elders and priests.