Complex sentence: Despite Culloden, he had a largely unsuccessful military career, and following the Convention of Klosterzeven in 1757, he never held active military command, and switched his attentions to politics and horse racing.
Split into simpler sentences: Despite Culloden, he had a largely unsuccessful military career. Following the Convention of Klosterzeven in 1757, he never held active military command, and switched his attentions to politics and horse racing.