He's completely bound to a wooden board, except for his left elbow to hand, enough to drink a beverage and eat, before scattering the rancid meat on the straps to entice rats to gnaw his way to freedom, just as the pendulum makes body contact.
The walls become red-hot, the room shrinks him so he has nowhere to go but the molten pit of iron, when all of a sudden trumpets sound and the French Army, General Lasalle at the helm, rescues him from the evil Inquisition prison. As good as can be expected in Poe's sensory horror thriller-- or is it all a hallucination tripped by mental illness?
His gift for writing about his own pain-- both physical and metaphysical-- keeps his readers coming back for more.: Both time periods in history are references, because Poe wants us to remember that persecution can be for many reasons.
Maybe that's why he doesn't clearly define the reason for the sentence.
Some 150,000 people were charged, 3,000 - 5,000 were believed to be executed.
Literary references may have exaggerated the extent of the torture, which makes it an effective reference in this story.
Poe's story is in the darkest reaches of Dark Romanticism, in the genre of Gothic Literature due to its focus on pure terror, utter despair, and physical torture.
Poe brilliantly applied his personal experience suffering from mental illness to his canon of works, so readers become emersed in his senses of madness, obsession with death, and the supernatural.
In this case, the Latin phrase at the beginning of the story is an epigraph, because even though Poe claimed it would be engraved on the gates of the Jacobin Club (see "Inaccurate Historical Context" section for more), it never was (if it had been, that would make it an "epitaph"). Poe chooses to write the epigraph in Latin, which was common for works of literature from the Renaissance through the 19th century.
His intent may have been to convince his readers the story was set during the Spanish Inquisition, even though it was at least three centuries later (see the section below: "Inaccurate Historical Context").