Complex sentence: Nelson invited Rose to go on board HMS Victory before the ship sailed for the Battle of Trafalgar; his purpose was to tell Rose that, if he was killed, he had left Lady Hamilton and their daughter Horatia to the Nation.
Split into simpler sentences: Nelson invited Rose to go on board HMS Victory before the ship sailed for the Battle of Trafalgar. Nelson's purpose was to tell Rose that, if he was killed, he had left Lady Hamilton and their daughter Horatia to the Nation.