Fabian Gottlieb Thaddeus von Bellingshausen was a Baltic German naval officer in the Imperial Russian Navy, cartographer and explorer, who ultimately rose to the rank of admiral. He participated in the First Russian circumnavigation of the globe and subsequently became a leader of another circumnavigation expedition that discovered the continent of Antarctica. – Wikipedia
Mikhail Petrovich Lazarev was a Russian fleet commander and an explorer; as a commander of the ship Mirny and von Bellingshausen’s deputy on his 1819–1821 world cruise in Lazarev took part in the discovery of Antarctica and numerous islands. On 28 January 1820 the expedition discovered the Antarctic mainland, approaching the Antarctic coast at the coordinates 69°21′28″S 2°14′50″W and seeing ice-fields there. – Wikipedia