But Pitt's spirit was still unbroken, and by the middle of July he succeeded in rallying three powers, Russia, Austria, and Sweden, into a league to withstand the further encroachments of France. Such a league had been proposed by Gustavus IV. of Sweden, early in 1804, but nothing definite was done till Pitt's ministry entered upon office. Meanwhile, the assassination of the Duke of Enghien had led to a rupture of diplomatic relations between France and Russia, though war was not declared. Negotiations were presently set on foot for a league, which, it was hoped, would be joined by Austria and Prussia in addition to Great Britain, Russia, and Sweden. An interesting feature in the negotiations was the tsar's scheme of a European polity, where the states should be independent and enjoy institutions "founded on the sacred rights of humanity," a foreshadowing, as it would seem, of the Holy Alliance. The discussion of details between Great Britain and Russia began towards the end of 1804. Difficulties, however, arose about the British retention of Malta and the British claim to search neutral ships for deserters. A treaty between the two powers was signed on April 11, 1805; but the tsar long refused his ratification, and it was only given in July, after a formal protest against the retention of Malta. The object of this alliance was defined to be the expulsion of French troops from North Germany, the assured independence of the republics of Holland and Switzerland, and the restoration of the King of Sardinia in Piedmont; 500,000 men were to be provided for the war by Russia and such other continental powers as might join the coalition. Great Britain, instead of furnishing troops, was to supply £1,250,000 a year for every 100,000 men engaged in the war. After the close of the war an European congress was to define more closely the law of nations and establish an European federation. At the same time the allies disclaimed the intention of forcing any system of government on France against her will. It will be observed that the number of troops specified was far in excess of what Russia alone could place in the field; such numbers could only be obtained by the adhesion of Austria and of either Prussia or some of the smaller German states to the coalition. So far as Austria was concerned, Napoleon's Italian policy rendered war inevitable. Already in November, 1804, the Austrian court had entered into a secret agreement with Russia to make war on France in the event of further French aggressions in Italy. The coronation of Napoleon as King of Italy and the annexation of Liguria were, however, more than aggressions; they were open violations of the treaty of Lunéville which had guaranteed the independence of the Cisalpine and Ligurian republics. Austria hereupon determined on war, and secretly joined the coalition on August 9, 1805. Sweden, which was not a member of it, concluded separate treaties of alliance both with Great Britain and with Russia.