The expedition left London in April, with Ross commanding , a vessel that the Admiralty had hired, and accompanied by , another hired vessel, under Lieutenant William Edward Parry. Ross sailed counter-clockwise around Baffin Bay repeating the observations made by William Baffin two hundred years before. In August, he entered Lancaster Sound at the north end of Baffin Island; this later proved to be the eastern gate of the Northwest Passage. He sailed a number of miles west but went no further, for he was misled by a mirage that appeared to show mountains at the end of the strait. He named the apparent mountains "Croker Mountains", in honour of John Wilson Croker, then first secretary of the Admiralty. He then returned to England despite the protests of several of his officers, including Parry and Edward Sabine, who thought he should have more thoroughly examined the "mountains".