This references Sir Ernest Shackleton’s 1907-1909 expedition to Antarctica in his ship of the same name. The Nimrod is considered one of the greatest ever Antarctic expeditions; it was on this journey that Shackleton and his companions Adams, Marshall and Wild discovered the Trans-Antarctic Mountains, found a way through this range and were the first people to set foot on the high polar plateau. Both Shackleton and Scott, like these heroes, journeyed to far away mythical lands to accomplish deeds of heroism and daring.
Sir Ernest Shackleton (1874 –1922) was an Anglo-Irish explorer and one of the principal figures of the Heroic Age of Antarctic Exploration. He was third officer on Captain Scott’s Discovery Expedition, 1901–04, from which he was sent home early suffering from malnutrition. He returned to Antarctica in 1907 as leader of the Nimrod Expedition. For his achievement, Shackleton was knighted by King Edward VII. After Amundsen attained the South Pole in 1912, Shackleton turned his attention to the crossing of the continent and returned for the Imperial Trans-Antarctic Expedition, 1914–17, known as the Endurance expedition. In 1921 he went back to the Antarctic with the Shackleton-Rowett Expedition, intending to carry out a programme of scientific and survey activities, but died of a heart attack while his ship, Quest, was moored in South Georgia. He is buried there. (Source: Wikipedia).