Modrý kríž (Slovak for Blue Cross) was a "teetotalers' society" originating in Stará Turá, Slovakia at the end of the 19th century and the beginning of the 20th. It was founded by sisters Kristína Royová and Mária Royová and initiated a movement in the spiritual, cultural and social life of the mainly peasant people of the surrounding region who traditionally belonged to the Lutheran Church.
The society encouraged its members to become born-again Christians by means of everyday prayers and Bible study, while forbidding the consumption of alcohol, smoking, playing cards and dice, blasphemous speech, and obsessions of a sexual or other kind.
The sisters were also active as authors and in charitable work.
International Federation of the Blue Cross