He was replaced in 1818 by an officer appointed from the Imperial Russian Navy. The position of Chief Manager was thereafter reserved for Imperial Naval officers. The Ukase of 1799 (edict or proclamation) granted the company a monopoly over trade in Russian America, defined with a southern border of 55° N latitude. Tsar Alexander I in the Ukase of 1821 asserted its domain to 45°50′ N latitude, revised by 1822 to 51° N latitude. This border was challenged by both Great Britain and the United States, which ultimately resulted in the Russo-American Treaty of 1824 and the Russo-British Treaty of 1825. These established 54°40′ as the ostensible southward limit of Russian interests. The only attempt by the Russians to enforce the ukase of 1821 was the seizure of the U.S. brig "Pearl" in 1822, by the Russian sloop "Apollon". The "Pearl", a vessel of the maritime fur trade, was sailing from Boston, Massachusetts to New Archangel/Sitka. When the U.S. government protested, the Russians released the vessel and paid compensation. Due to treaty violations in 1833 with the British by the company's governor, Baron Ferdinand von Wrangel, the Russians later leased the southeastern sector of what is now the Alaska Panhandle, to the Hudson's Bay Company in 1838 as part of a damages settlement. The lease gave the HBC authority as far north as 56° 30' N. Under Baranov, who governed the region between 1790 and 1818, a permanent settlement was established in 1804 at "Novo-Arkhangelsk" (New Archangel, today's Sitka, Alaska), and a thriving maritime trade was organized. Alutiiq and Aleut men from the Kodiak and the Aleutian Islands were forcibly conscripted to work for the company for three-year periods because they were "among the most sophisticated and effective sea otter hunters in the world." During its initial years, the company had problems in maintaining a pool of skilled crewmen for its ships. The limited number of Russian men proficient in naval craft in the Empire usually sought employment in the Imperial Russian Navy. The RAC had difficulty recruiting men for naval training, in part due to the continued practise of serfdom in the Empire, which kept most peasants tied to the land. In 1802 the Imperial government directed the Imperial Navy to send officers for employment in the RAC, with half of their pay to come from the company.