red flag/rag to a bull, like a

red flag/rag to a bull, like a

Inflammatory, infuriating. This simile is based on the ancient belief that bulls react more strongly to a piece of red cloth waved before them than to anything else. In bullfighting the matador’s cape, which he manipulates so as to maneuver the bull’s movements, is usually lined in red. However, it has been fairly well established that it is the cape’s movements that incite the bull; the red color simply makes it more visible to the spectators. Nevertheless, as early as the sixteenth century the belief that red incites bulls was recorded by John Lyly (Euphues and his England, 1580), who wrote, “He that commeth before an Elephant will not wear bright colours, nor he that commeth to a Bul red.”
See also: flag, like, rag, red