Lhotse is 610 meters (2,000 feet) above the lowest point of South Col, which is enough to consider it as a separate mountain range. If the topographical protrusion height of Lhotse is less than 500 meters, it will be regarded as an auxiliary peak of Mount Everest.
Nevertheless, climbers often combine the two together. Lhotse is sometimes called the southern peak of Mount Everest. In 1956, a Swiss team reached Lhotse for the first time, the same as their second summit of Everest. They walked along the route from South Col Mountain to the west of Lhotse.