What is the origin of the upside down cross?

The upside-down cross, also known as the inverted cross, has been associated with various meanings throughout history. One of the earliest known uses of the upside-down cross is as a symbol of St. Peter, one of the twelve apostles of Jesus Christ. According to tradition, St. Peter was crucified upside down as he believed he was unworthy to be crucified in the same manner as Jesus. Over time, the upside-down cross has also been used in various contexts, including as a symbol of rebellion or as a representation of anti-Christian beliefs.