This 30 mm tube diameter „Certar 4 ½ x” is one of the first generation of German rifle scopes. I found it advertised first in 1900. By 1910 it had disappeared from catalogs and ads already. As Goerz became an AG in 1904, this scope was probably made 1900 – 1904.
The maker, the C.P.Goerz of Berlin, was founded by Carl Paul Goerz, 1854 – 1923. At the time of WW1 they were the largest optics maker worldwide. They offered all kinds of optical articles, from cameras and science apparatus to artillery sights and the superior rangefinders of the navy. Making military supplies only during the Great War, Goerz was in troubles under the conditions of Versailles. In 1926 they amalgamated with Zeiss, Jena. The Berlin factories were taken over by the soviets in 1945 and all equipment, including personnel, transported to Russia.