The belief that breaking a mirror brings seven years of bad luck is a superstition that has roots in several historical and cultural contexts. Here are a few interpretations and origins:

1. Ancient Beliefs: Mirrors were once believed to possess magical qualities, reflecting not just a person’s image but also their soul or essence. Breaking a mirror would thus damage or fragment the soul, causing spiritual harm that could manifest as bad luck for a period of time.
2. Roman Lore: The concept of seven years of bad luck may stem from the Romans, who believed that life renewed itself every seven years. Thus, the curse would last until the body and soul had undergone a complete cycle of renewal.
3. Medieval Europe: During the Middle Ages, mirrors were expensive and precious objects, often associated with wealth and status. Breaking one was considered a waste and an act that invited misfortune due to the loss of such a valued possession.
4. Superstition About Reflection: Some folklorists suggest that the idea came from a time when people believed that a reflection captured a moment in time and breaking it disrupted the natural order of things, inviting bad luck.
5. Christian Tradition: There is also a Christian tradition that held that mirrors should be covered during mourning because they could trap the soul of the deceased. Breaking a mirror inadvertently trapping a soul might bring about a curse lasting seven years, the length of time traditionally associated with biblical jubilee cycles and penance.

In reality, there is no empirical evidence linking broken mirrors to actual misfortune, and the belief is purely a superstition that has endured through generations.