Geodesy commemorates this year the foundation of the “Mitteleuropäische Gradmessung”, which started its activities 150 years ago. Originated from an initiative of the Prussian General Baeyer, this regional geodetic project required international cooperation. Outstanding organization soon led to a scientific body which continuously extended over the globe and finally built a global network of geodetic science, represented today by the “International Association of Geodesy” (IAG). The following paper first remembers the start of international cooperation at the beginning of modern geodesy, as realized through the arc measurements of the 18th and the early 19th century. First attempts for arc measurements covering central Europe then are found in the first half of the 19th century – connected with the names of Zach, Schumacher, Gauß, Müffling, Bessel and Struve, among others. Based upon a memorandum presented 1861, Baeyer proposed a coordinated proceeding and clearly defined the problems to be solved. This idea soon led to a governmental supported project and an organization which rapidly extended beyond the boundaries of central Europe. This early phase of international cooperation is discussed in more detail. Finally, the later extension of this early structure to a global scientific organization and the increasing incorporation into interdisciplinary geoscientific research is shortly described.