 In 1811, and again in 1818, projects of Asiatic exploration were proposed to Humboldt, first by Czar Nicolas I's Russian government, and afterwards by the Prussian government; but on each occasion, untoward circumstances interposed.It was not until he had begun his sixtieth year that he resumed his early role of traveler in the interests of science.The Russian Foreign Minister, Count Georg von Cancrin contacted Humboldt about whether a platinum-based currency was possible in Russia and invited him to visit the Ural Mountains.