Paint maker Diesbach of Berlin (Germany) had accidentally invented the pigment Prussian blue, a powerful dark blue pigment with greenish undertones (made from alum and animal bones), around 1706.

One of the first synthetic pigments, Prussian blue is employed as a very fine colloidal dispersion, as the compound itself is not soluble in water.

It is famously complex, owing to the presence of variable amounts of other ions and the sensitive dependence of its appearance on the size of the colloidal particles formed when it is made.

The pigment replaces the expensive lapis lazuli and is an important topic in the letters exchanged between Johann Leonhard Frisch and the president of the Royal Academy of Sciences, Gottfried Wilhelm Leibniz, between 1708 and 1716.

Frisch, for whom Diesbach had been working since about 1701, had begun to promote and sell the pigment across Europe not later than 1708.

It is first mentioned in a letter written by Frisch to Leibniz, from March 31, 1708.

The pigment had been termed "Preussisch blau" by August 1709; by November, the German name "Berlinisch Blau" had been used for the first time by Frisch.

Frisch himself is the author of the first known publication of Prussian blue in the paper Notitia Coerulei Berolinensis nuper inventi in 1710, as can be deduced from his letters.