Bloody flag
Pattern-free red flags, often called bloody flags, or the bloody red (among other names, see § Names), were the traditional nautical symbol in European waters, prior to the invention of flag signal codes, to signify an intention to give battle, and that 'no quarter would be given', indicating that surrender would not be accepted and all prisoners killed, but also vice versa, meaning that the one flying the flag would fight to the last man (defiance to the death). Such flags were traditionally plain but examples with motifs also existed, such as skull and crossbones on some pirate examples (see Jolly Roger).