Duke Harold of Pseudopolis was a client of the Assassins' Guild. He did not die easily. His bespoke personal Assassin had to resort to a cudgel, a length of chain, pistol crossbow, dagger, poison, and ultimately to attaching the man to an anchor, chopping a hole in a frozen river's ice, and pushing him in. The Duke did die, but three months later, of a chill he caught from the frigid dunking.
Shades of Rasputin, whose assassination was nearly as messy and difficult.