Formerly used by the vikings, this northernly land is located on the Dvina River, near the White Sea. In 1584, Ivan the Terrible founded the Archangel Michael Monastery and the city became known as Arkhangelsk. During this time, the Baltic Sea was owned by Sweden, so the White Sea, and consequently Arkhangelsk, were Russia's most important sea trade centers. However, Peter I knew that because the sea froze for five months of the year, it would be better to build a port near the Baltic Sea, so in 1704, St. Petersburg was established and Arkhangelsk was no longer allowed to trade, for the next 40 years. However, during both World Wars, Arkhangelsk once again became a major trade center for Allied aid, when Russia could not use its normal trade ports for supplies.