Saint Michael the Archangel and Satan were neighbours. One evening in winter they held the vigil together and were talking. Satan affirmed that he was almighty. Saint Michael believed that only God is almighty. “Okay,” said Satan: “call God for help and build a castle, I will build one as well, and the one, that builds the most beautiful castle, wins.” Saint Michael accepted the bet.
Satan sent his imps in all regions of the world. They brought granite blocks and Satan used them to pile up a mountain on a small isle. Then he built a huge granite castle on the mountain.
Saint Michael used ice crystals to build a castle of ice on the sands. The sun was scintillating on it’s columns and frets.
Satan had to admit that the ice castle was more beautiful than the granite castle. He was jealous and wanted the ice castle for himself. Thus he asked if Saint Michael would exchange the castles. Saint Michael agreed and they swapped castles.
Then the summer came and the ice castle was melting. The granite castle is still standing, it is the Mont-Saint-Michel.
Les Légendes Normandes, by Louis Bascan, a collection of Norman legends of older sources, reprint of 1929 published by “les Editions du Bastion”, 1999, ISBN=2745500503, page 9f, French
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