Complex sentence: All parties agreed, included the Prince of Solms-Braunfels, whose sudden death on 13 April 1814 was considered by some too convenient, suspecting Frederica of poisoning her husband.
Split into simpler sentences: All parties agreed, included the Prince of Somls-Braunfels. The death of the Prince of Solms-Braunfels on 13 April 1814 was considered by some too convenient, suspecting Frederica of poisoning her husband.