"The J.P. Kayser firm has its seat in Krefeld-Bockum and Cologne. It was predominantly a pewter manufactory. In 1862 the tin-foundry was moved from Kaiserswerth to Krefeld-Bockum by J.P. Kayser and in 1855 it was considerably enlarged and modernized. Around 1900 Engelbert, his son, set up a studio for the art of pewter in Cologne where the designs and models for the foundry were produced. The foundry was under the exclusive direction of his brother, Johann Peter Kayser Jun., who insisted that Kayser pewter be exhibited at all international exhibitions. Kayser foundry developed new sensational techniques of tin founding. This was the so-called "Kayser Pewter", which was characterized by an especially silvery sheen and took a splendid polish. It was made of block tin with large additions of copper and antimony. This alloy produced the silvery gleam and above all made the vessel walls much stronger. The numbering of individual pieces started from 4,000." The two main designers for Kayserzinn were Hugo Leven and Carl Bergholz.
Wichmann, Siegfried. (1984). Jugendstil Art Nouveau. Germany: Schuler Verlag. New York: Little, Brown and Company.