How long did it take to execute someone in a brazen bull?

Answer 1

The brazen bull history:

The Brazen Bull was invented by Perilaus of Athens (a Brass worker) in the 6th Century BC and offered to Phalaris, Tyrant of Agrigentum, as a gift. It was a large brass bull that was completely hollow inside with a door on the side large enough for a man to enter. Once the man was inside the bull, a fire would be lit beneath it in order to roast him to death. In the head of the bull, Perilaus put a series of tubes and stops that were designed to amplify the screams of the victim and make them sound like the roar of a bull.

Interestingly, Perilaus was the first person to feel the pain of the Brazen Bull. After Perilaus said to Phalaris: "[his screams] will come to you through the pipes as the tenderest, most pathetic, most melodious of bellowings", Phalaris was so disgusted that he tricked Perilaus in to entering the bull. Lucian recounts the tale:

'His words revolted me. I loathed the thought of such ingenious cruelty, and resolved to punish the artificer in kind. "If this is anything more than an empty boast, Perilaus," I said to him, "if your art can really produce this effect, get inside yourself, and pretend to roar; and we will see whether the pipes will make such music as you describe." He consented; and when he was inside I closed the aperture, and ordered a fire to be kindled. "Receive," I cried, "the due reward of your wondrous art: let the music-master be the first to play." Phalaris I:12

Perilaus was removed from the Bull before he died and Phalaris had him thrown off a cliff. The Brazen Bull became one of the most common methods of execution in Ancient Greece.

--Listverse--

I guess that back in the 6th century there were no clock to measure the time that took a person to die in the braze bull since no records exist to tell how much time it took.