Complex sentence: Such was his reputation that the attack on Te Porere near Tongariro was delayed until Te Keepa and his men arrived; they were marching up the Whanganui River in the face of snowstorms and volcanic eruptions.
Split into simpler sentences: Such was his reputation that the attack on Te Porere near Tongariro was delayed until Te Keepa and his men arrived. They marched up the Whanganui River in the face of snowstorms and volcanic eruptions.