"The first active gangs in Western civilization were reported by Pike (1873, pp. 276--277), a widely respected chronicler of British crime. He documented the existence of gangs of highway robbers in England during the 17th century, and he speculates that similar gangs might well have existed in our mother country much earlier, perhaps as early as the 14th or even the 12th century. But it does not appear that these gangs had the features of modern-day, serious street gangs. More structured gangs did not appear until the early 1600s, when London was 'terrorized by a series of organized gangs calling themselves the Mims, Hectors, Bugles, Dead Boys … who found amusement in breaking windows, [and] demolishing taverns, [and they] also fought pitched battles among themselves dressed with colored ribbons to distinguish the different factions.'"
National Gang Center: http://www.nationalgangcenter.gov
National Gang Center Bulletin (May 2010), no.4