Before railways and banks, an escort agency,
镖局, hired out armed guards called
镖客 or
镖师 to take silver, goods and travellers safely along roads troubled by bandits. Chinese film titles later lent the word to the lone gunmen of westerns: Sergio Leone's Dollars films are the
镖客三部曲, and The Good, the Bad and the Ugly is
黄金三镖客.