Oliver Nos. 2, 3, and 4 were distributed throughout Europe by a company called Fabrik Stolzenberg (Stolzenberg Factory). They were based in Oos Baden-Baden, a city in Baden-Württemberg in southwestern Germany, with subsidiaries in Berlin, Hamburg, and Cologne.
Fabrik Stolzenberg sold the Oliver No. 2 as the Oliver Monopol-Stolzenberg. This name initially carried over to the Oliver No. 3. Sometime between serial numbers 55756 and 89075, the "Monopol" was dropped and the Oliver 3 machines were branded as "Stolzenberg". Once the Oliver No. 4 was introduced 1904, Fabrik Stolzenberg sold it as the Oliver Stolzenberg No. 4.
The serial numbers for the Oliver Monopol-Stolzenberg and Stolzenberg models are intermixed with their respective serial number range. Therefore, it is hard to know how many of each model were distrubuted by Fabrik Stolzenberg. I have the only Monopol-Stolzenberg No. 2 known to exist. I know of three Monopol-Stolzenberg No. 3 machines in existance. The Oliver Stolzenberg No. 3 is by far the most common Stolzenberg model; there are so many that I have lost count. In contrast, I only know of two Oliver Stolzenberg No. 4 machines in existance.