A crucible is a container made to heat metal at high temperatures. As such, it is extremely tough and durable. A crucible is also defined as a severe test or trial. The Burning Times certainly were a crucible for witches and anyone suspected of witchcraft.
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In 1951, the English Parliament repealed its surviving laws against witchcraft.
Two years later, Arthur Miller's play 'The Crucible' was a hit on Broadway. Historically and culturally, this was a turning point for witches. Not only did witchcraft reemerge into public discussion, but the witch-hunts were seen for what they were - persecution for no good reason.
Arthur Miller's play is a work of art, not history and he took many liberties with the actual facts. That he was able to use the Salem trials as a metaphor indicates that the tide of irrational hatred against witches was beginning to turn.