Probably founded at Zülpicherstraße 85, next to the university, circa 1883. Heinrich Worringen had a shop at Altermarkt 47 and it is believed that for a period around 1907 - 1911, or even later, Gustav Vater shared premises with him. Vater might even have been the supplier of Worringen's porcelain decoration service. At sometime, the spelling of Altermarkt was changed to Alter Markt. In the 1920's Vater moved to Bahnstraße, which is now a residential area.
The German spelling for Cologne, varied over the years. So in 1900 the Prussian Minister for Interior Affairs, issued an edict that the correct spelling for Cologne was Cöln. However, on the 1st February 1919, the mayor of Cologne, Konrad Adenauer, stated the official name was again Köln. Probably most people continued to use the spelling they preferred.
Purchased stein bodies from: Villeroy & Boch - Mettlach, Merkelbach & Wick Wicke-Werke.
Reference: bilderbuch-koeln
Student stein, dated 1929
Basemark on the student stein above. 
Student coat of arms on Villeroy & Boch, Mettlach stein
Wick-Werke (post 1922) stein with Student coat of arms
Student coat of arms on Villeroy & Boch, Mettlach #1526, dated 1903 
Student coat of arms on Villeroy & Boch, Mettlach #1526. The Mettlach factory ceased production in 1921. 
"Nirsia sei's Panier" This stein was dedicated to someone in the Catholic Theological Association in 1907. 
Base mark on the featured stein, above, of decorator together with the impressed mark of Merkelbach & Wick. 