Short answers, pulled from the story.
Fabian Gottlieb von Bellingshausen was a Russian admiral and cartographer of Baltic German descent who led the expedition that discovered Antarctica on the 27th of January 1820. He commanded the sloop Vostok during the Russian circumnavigation of 1819-1821 and also participated in the first Russian circumnavigation of the globe from 1803 to 1806.
Bellingshausen and his second-in-command Mikhail Lazarev sighted the Antarctic mainland on the 27th of January 1820 (New Style), at coordinates 69 degrees 21 minutes 28 seconds south, 2 degrees 14 minutes 50 seconds west. British polar historian A. G. E. Jones confirmed in his 1982 study Antarctica Observed that this was three days before Edward Bransfield and nearly ten months before Nathaniel Palmer.
Bellingshausen commanded the 985-ton sloop-of-war Vostok, while Mikhail Lazarev captained the 530-ton support vessel Mirny. The two ships departed Kronstadt on the 4th of June 1819 and returned on the 4th of August 1821, circumnavigating the Antarctic continent twice without losing sight of each other.
During the 1819-1821 expedition, Bellingshausen discovered and named Peter I Island, Zavodovski Island, Leskov Island, Visokoi Island, and the Alexander Coast (now known as Alexander Island). The expedition also made observations in the tropical Pacific and visited the South Shetland Islands and Meretoto (Ship Cove) in New Zealand.
Bellingshausen reached the rank of admiral in 1843, the highest rank in the Russian naval hierarchy. He was promoted to counter admiral by Tsar Nicholas I in 1826, to vice admiral in 1830 after fighting in the siege of Varna during the Russo-Turkish War of 1828-1829, and served as military governor of Kronstadt from 1839 until his death in 1852.
The Bellingshausen Sea in the Southern Ocean, Bellingshausen Station on King George Island in Antarctica, Bellingshausen Island in the South Sandwich Islands, and the minor planet 3659 Bellingshausen (discovered by Soviet astronomer Lyudmila Chernykh in 1969) all bear his name. A crater on the far side of the Moon and an atoll in the Pacific Society Islands known as Motu One are also associated with him.