Crowned heads, wealth and privilege may well tremble should ever again the Black and Red unite!

Frequently quoted in online leftist circles. Refers to the split of the First Internationale (between anarchists and socialists). The earliest mention is on page 95 of American radicalism, 1865-1901, essays and documents (1946) by Chester McArthur Destler, but as of now the German original could not be found.

In German political parlance, "black" more often referred to Catholic interests than to anarchism; it is possible that if Bismarck did say this, it referred rather to a union between the Catholic Center and the Socialist "reds" against the German nationalist/Protestant "blues."