Thus it was as Political Secretary to the Foreign Office that he determined policy in the 1890s. It was almost entirely due to him that Germany acquired Tsingtao (now Qingdao) and asserted German interests in China; the acquisition of Samoa was also largely his work. If the skill and pertinacity with which Holstein carried through his plans in these matters was learned in the school of Bismarck, he had not acquired Bismarck's faculty for foreseeing their ultimate consequences. This is seen by blunders made on the abandonment of the Reinsurance Treaty with Russia in 1890, his Chinese policy, and also of his part in the Moroccan crisis which led to the Algeciras Conference in 1906. The Kaiser's journey to Tangier was undertaken on his advice, as a protest against the supposed attempt at Germany's isolation. Holstein did not approve the later developments of German policy in the Morocco, on the ground that the result would merely be to strengthen the Anglo-French entente. From 12 March 1906 onward he took no active part in the matter and resigned one month later.