Nailing the colours (also nailing the colours to the mast or nailing the flag) is a practice dating back to the Age of Sail that expresses a defiant refusal to surrender, and willingness to fight to the last man. During the Age of Sail, ships would legally fight only while flying their national flag. Flying another flag was considered to be a legitimate ruse de guerre only until the beginning of the fight. Striking the colours was a sign of surrender. Indeed, when cannon shots fell a ship's flag, her opponent would cease firing and inquire whether she was capitulating.