After commercial intercourse was established with England, and British traders settled in Moscow, Ivan continued to show them his favor. He was himself the greatest merchant of Russia. The furs which he received from Siberia were sold to the foreign merchants at the fairs. His agents went into the provinces where they compelled the people to sell him furs, wax, honey, etc., at such prices as he chose to pay, and the foreign merchants had to buy them from him at a high price. He also bought the imported goods and sold them to Russian merchants. They were not permitted to buy from anybody else, until the goods (p. 119) of the czar were sold. At the beginning of his reign, in 1551, Ivan was preparing an expedition to Kazan, and in June of the following year he descended the Volga and laid siege to that city. It was captured after a brave defense, when a number of the people were massacred and the rest sold as slaves. This conquest was followed by that of Astrakhan in 1554; the Volga from its source to its mouth was thereafter a Russian river. The Cossacks of the Don also submitted to him. The European countries bordering on Russia dreaded that country's growing power. Ivan, after his coronation, sent to western Europe to engage a number of engineers and mechanics; these men were stopped on the road, and none of them ever reached Moscow. Sigismund of Poland even threatened to kill the British merchants on the Baltic, "because," he said, "if the Muscovite, who is not only our present adversary, but the eternal enemy of all free countries, should provide himself with guns, bullets, and munitions; and, above all, with mechanics who continue to make arms, hitherto unknown in this barbaric country, he would be a menace to Europe." Ivan, on the other hand, was equally anxious that the Russians should possess all the advantages of Europe's superior civilization. This, added to the inherited hostility between the two countries, caused many wars. While Ivan was pursuing his conquests in the south, he was attacked by Gustavus Wasa, Sweden's famous king, who entertained the same fears as the King of Poland. The war ended by a commercial treaty whereby (p. 120) Swedish merchants might trade with India and China by way of Russia, and those of Russia with Holland, England, and France by way of Sweden. This war had scarcely ceased before envoys of the Livonian Order arrived to request a renewal of the truce. Ivan demanded tribute for Iourief which he claimed as his "patrimony." This was refused, and war was declared. It was owing to Ivan that this brotherhood was dissolved and its territory divided. In 1566, a truce was proposed by Poland.