The fountain is called the Executioner's Fountain, because here he rinsed his sword and washed his hands after carrying out his orders; examples of his handiwork were displayed on pikes at the Imperial Gate.
The Executioner's Fountain is so named because it's the place where the executioner cleaned his sword.
mnli hypothesis: The Executioner's Fountain is so named because it's the place where the executioner cleaned his sword. premise: The fountain is called the Executioner's Fountain, because here he rinsed his sword and washed his hands after carrying out his orders; examples of his handiwork were displayed on pikes at the Imperial Gate.