Question: Helmer Julius Hanssen, was a Norwegian sailor, pilot and polar explorer, he participated in three of the polar expeditions led by Roald Engelbregt Gravning Amundsen, was a Norwegian explorer of polar regions, he was the leader of the Antarctic expedition of 1910–12, which was the first to reach the South Pole, on which date?
Sentence (from "Roald Amundsen"): As the leader of the Antarctic expedition of 1910–12, which was the first to reach the South Pole, on 14 December 1911, he was a key expedition leader during the Heroic Age of Antarctic Exploration.
Relevant evidence: Yes