"...the streets and parlors of Belgrade, Bucharest and Sarajevo emerged as Europe's critical battlefield, as the various Great Powers began to toy with innovations in spycraft. Despite its much-debated "turn from Europe," Russia still viewed Orthodox Southeast Europe as its backyard and deployed a number of avenues for influence, both diplomatic and clandestine, with a well-developed network of agents of influence, particularly in Serbia, where it sought to drum up support for the return of the Karadordevic dynasty. It was this activity - and the awareness that the Information Bureau in Vienna had of it - that created the biggest wedge between Austria and Russia and stymied France's desires for a burying of the hatchet between Habsburg and Romanov to form an isolating vise around Germany from which Paris' fiercest foe could never practically break free. [1] Germany, for her part, did not have as active a presence in the Balkans compared to Austria, Russia and France - which practically governed Montenegro from the offices of its embassy, treating Nicholas I as little more than a satrap - choosing instead to focus entirely on continuing to cultivate its relationships in Romania via the ruling Hohenzollern cadet house there. Nevertheless, for all of Berlin's lacking in a formal spy network, it enthusiastically used a different tactic - that of guns and butter - to keep Romanian officials happy, while quietly letting Russia regain small footholds of influence there and keeping its "Danube Policy," as Chancellor Hohenlohe called it, roughly in alignment with Moscow's interests in order to prevent the worst-kept secret of European power politics, that of Paris' "grand encirclement," from coming to fruition.
Britain, for its part, exercised perhaps the most diverse spy network of them all, embedded in merchant houses, naval liaison offices, and increasingly, the local press. Istanbul was the tip of the spear for Albion's influence campaign in Southeast Europe, by the early 1890s using its considerable sway in Persia and the Gulf to dangle carrots before the Porte, as well as a writedown of Turkish debts to protect its beleaugured banking industry in the wake of 1890, and gradually having some of the most robust information on the goings-on of the affairs of state in the Balkans via a legion of affable Ottoman bureaucrats and businessmen..."
- Shadow Wars: A History of Espionage and Counterintelligence
[1] More on this later!