Here again the master-builder was Bismarck. As he had concentrated all the powers of his mind on the completion of German unity (with its natural counterpart in Italy), so, too, he kept them on the stretch for its preservation. For two decades his policy bestrode the continent like a Colossus. It rested on two supporting ideas. The one was the maintenance of alliance with Russia, which had brought the events of the years 1863-70 within the bounds of possibility; the other aim was the isolation of France. Subsidiary notions now and again influenced him, as in 1884 when he sought to make bad blood between Russia and England in Central Asian affairs (see Chapter XIV.), or to busy all the Powers in colonial undertakings: but these considerations were secondary to the two main motives, which at one point converged and begot a haunting fear (the realisation of which overclouded his last years) that Russia and France would unite against Germany. In order, as he thought, to obviate for ever a renewal of the "policy of Tilsit" of the year 1807, he sought to favour the establishment of the Republic in France. In his eyes, the more Radical it was the better: and when Count von Arnim, the German ambassador at Paris, ventured to contravene his instructions in this matter, he subjected him to severe reproof and finally to disgrace. However harsh in his methods, Bismarck was undoubtedly right in substance. The main consideration was that which he set forth in his letter of December 20, 1872, to the Count:--"We want France to leave us in peace, and we have to prevent France finding an ally if she does not keep the peace. As long as France has no allies she is not dangerous to Germany." A monarchical reaction, he thought, might lead France to accord with Russia or Austria. A Republic of the type sought for by Gambetta could never achieve that task. Better, then, the red flag waving at Paris than the _fleur-de-lys._ Still more important was it to bring about complete accord between the three empires. Here again the red spectre proved to be useful. Various signs seemed to point to socialism as the common enemy of them all. The doctrines of Bakunin, Herzen, and Lassalle had already begun to work threateningly in their midst, and Bismarck discreetly used this community of interest in one particular to bring about an agreement on matters purely political. In the month of September 1872 he realised one of his dearest hopes. The Czar, Alexander II., and the Austrian Emperor, Francis Joseph, visited Berlin, where they were most cordially received. At that city the chancellors of the three empires exchanged official memoranda--there seems to have been no formal treaty[242]--whereby they agreed to work together for the following purposes: the maintenance of the boundaries recently laid down, the settlement of problems arising from the Eastern Question, and the repression of revolutionary movements in Europe.