Complex sentence: Wickaninnish was a rival of the Mowachaht chief Maquinna of Nootka Sound and in one account is blamed for the death of Maquinna's brother, Callicum, an event which spurred a war by the Mowachaht against the Tla-o-qui-aht.
Split into simpler sentences: Wickaninnish was a rival of the Mowachaht chief Maquinna of Nootka Sound. In one account he was blamed for the death of Maquinna's brother, Callicum, an event which spurred a war by the Mowachaht against the Tla-o-qui-aht.