History of the Superstitions about Ladders
Ladders as Symbols
Ladders tend to symbolize an individual's quest for upward movement. This may be through spiritual ascension, as the person's soul ascends to Heaven, or it may just be through normal movement, be it an ascension in class and financial status, or in stages of life, such as getting married. Because it is often associated with these things, to violate it could mean bringing about bad luck on oneself. One of the most common ways is to walk under a ladder, but why has this gained so much popularity as a superstition?
The myth has different origins, one of which dates all the way back to ancient Egyptian times. Ladders would be placed in the tombs by Egyptian priests so that the dead could ascend the stairs if they wished. Spirits were though to gather in the space between the leaning ladder and the wall. As many students know when they get to trigonometry, when a ladder leans against a wall, it creates a natural triangle, with the ladder, wall, and ground acting as its sides. Triangles have often been regarded as sacred. In ancient Egypt, they believed that triangles held power because they were the shape of a pyramid. The spirits gathered under the ladder, evil and benign, could potentially grab hold of a person walking though them. However, there are always ways to ward off the bad luck if one catches it quick enough. In this case, if the person placed their thumb between their index and middle fingers, they could ward off the bad spirits.
Christian and European Superstition
In medieval times, Europeans associated a leaning ladder with the gallows, as many impromptu gallows were created using ladders. Walking under a ladder guaranteed one's death by hanging. Another explanation is that Europeans would cut down the dead body after a public hanging, using a ladder to get up to the rope. Walking under the ladder meant that one might be hit by a dead body, undoubtedly an unpleasant experience. Some Scottish lore says that you may be granted a wish if you are forced to walk under a ladder.
Remember how triangles were said to hold power? They have three sides, and people speculate in the power of three. In Christian superstition, the triangle created by a ladder symbolizes the Holy Trinity. If one walked through that triangle, one is believed to be violating and desecrating God. To prevent bad luck, superstition says to cross fingers on both hands, calling on the cross to banish evil. Others advise to spit three times for the Blessed Virgin, the Son, and the Holy Ghost, to banish bad spirits.
If anyone else knows more about these superstitions, please feel free to add it in the comments!