the rope isn't really necessary: First he wanted to hang himself, and when that didn't work, he drowned himself (or tried to drown himself)in the pond in the Teplitz castle gardens.

Agree with the kat that rope is unnecessary. But for the record,
"shall be hanged by the neck until dead" is the judge's sentence.
He hanged himself with his belt in his cell (sorry to be so gruesome!) is the method.