The Catherine wheel is a type of firework consisting of a powder-filled spiral tube, or an angled rocket mounted with a pin through its centre. When ignited, it rotates quickly, producing a display of sparks and coloured flame. The firework is named for the wheel on which St. Catherine was martyred.
Catherine's story relates how she is said to have visited the Roman Emperor Maxentius and to have attempted to convince him of the error of his ways in persecuting Christians. Her legend states that Catherine succeeded in converting his wife, the Empress, and also many pagan wise men sent to dispute with her by the Emperor, all of whom were subsequently martyred. The Emperor ordered Catherine into prison, and when the people who visited her converted, she was condemned to death on the breaking wheel (an instrument of torture). The wheel itself broke when she touched it, so she was beheaded.