According to one of them, prince Henry the Fourth wanted to become a king, but the consent of a pope was needed to be granted such a privilege.
The said consent was granted after offering the pope a significant amount of gold, but the treasury of the king-to-be was empty.
Therefore, he decided to visit a fortuneteller, who transformed soldiers of the king into pigeons, which then sat at the top of the St. Mary Basilica and started chipping small stones off the building.
Each particle that fell to the ground changed into gold. Thanks to the said transformation and help of the pigeon soldiers, Henry the Fourth was able to gather 3 carts of gold and travel to Rome. After his return, he was greeted by his soldiers, who returned to their former self. However, rumor has it that Henry the Fourth spent his gold on women and wine, never even reaching Rome.
Since time immemorial, there has been always a large flock of pigeons in a close proximity to the basilica at any time of day and night.