In England, sable fur was held in great esteem. Henry I was presented with a wreath of black sable by the Bishop of Lincoln, for no less than £100, a considerable sum at the time. Sable fur was a favourite of Henry VIII, who once received five sets of sable fur worth £400 from Emperor Charles V. Henry later decreed that sable fur was to be worn only by nobles exceeding the rank of viscount. The Russian conquest of Siberia was largely spurred by the availability of sables there. Ivan Grozny once demanded an annual tribute of 30,000 sable pelts from the newly conquered Kazan Tatars, though they never sent more than a thousand, as Russia at the time was unable to enforce the tribute due to wars with Sweden and Poland. The best skins were obtained in Irkutsk, Kamchatka, and Lapland.