In 1869, German missionaries established the first German presence in the territory that would become German East Africa. In 1884, the Company for German Colonization was founded by German explorer Carl Peters, and immediately began establishing treaties with local chiefs in the coastal region.

Over the next decade, the newly-founded German East Africa Company would increase German influence in the area by opening customs houses and forming agreements with local chiefs and Sultans. In the last years of the 1880s, however, Arabs opposed to the increased European presence began raiding and killing German settlers. The German East Africa Company requested assistance from the Imperial government, which quickly came in the form of ships and men under the command of newly-appointed Imperial Commissioner Hauptmann Hermann von Wissmann. Within a year, the insurrection was crushed, and in 1891, Germany acquired sovereignty over the entire territory.

With the outbreak of World War I, mail to and from German East Africa was subject to censorship.  Main from Germany to German East Africa was typically censored at one of several Auslandsstelle, with the most common censorship offices being Auslandsstelle Emmerich and Auslandsstelle Cöln-Deutz.  The censorship marks from these offices are typically a circular mark in red ink.