Cook's claim to have reached the North Pole on the 21st April, 1908, published on 2nd September, 1909, just 4 days ahead of Peary's rival claim (see Peary's North Pole), sparked one of the most bitter feuds in Polar exploration. Both parties to the dispute had their supporters, but opinion on the matter gradually swung in favour of Peary. Cook's own published account marshals evidence in support of his claim, and offers a discussion of the controversy.