Complex sentence: Because these accounts contained no illustrations, the Tahitian models in any case long disappeared, he was allowed free exercise of his imagination and executed some twenty paintings and a dozen woodcarvings over the next year.
Split into simpler sentences: Because these accounts contained no illustrations and the Tahitian models were in any case long disappeared, he could give free rein to his imagination. He executed some twenty paintings and a dozen woodcarvings over the next year.