In 18 century a Frenchman Henri Mission, who was visiting Britain, asked villagers why they had horseshoes nailed above their doors. He was told that it was to keep witches away. Horseshoes are made of iron, so the strengh of the iron is believed to protect from evil. Still today they are thought to bring good luck, but it's very important to position it upwards like a cup, so that the luck wouldn't fall out.
Story: A long time ago an unknown person came to a blacksmith and wanted to take his soul. The blacksmith was very strong, and he hugged the unknown. The unknown screamed in pain and prayed for his release. The blacksmith told him that I released you with a condition that if you will see at the entrance to the houses of the people a horseshoe to pass by and do not harm them.
Thank you:)
Good to know!