How did walking under a ladder to give bad luck originate?

The superstition that walking under a ladder brings bad luck likely originates from the triangular shape formed by a ladder leaning against a wall, which symbolizes the Holy Trinity in Christianity. Disturbing this triangle was thought to offend the divine. Additionally, in ancient Egypt, ladders were associated with the afterlife, and passing under one was seen as a way to disturb spirits. Over time, these beliefs merged into the modern superstition we recognize today.