Complex sentence: The English king brought him up in the Christian religion, and on the news of his father's death provided him with ships and men for an expedition against his half-brother Eirik Bloodaxe, who had been proclaimed king.
Split into simpler sentences: The English king brought him up in the Christian religion. On the news of his father's death King Athelstan provided Haakon with ships and men for an expedition against his half-brother Eirik Bloodaxe, who had been proclaimed king.