The article traces the controversy between J. N. De l'Isle and Gerhardt F. Müller in the mid‐18th century as to the discoveries made by the Great Northern Expedition (1733 1743) under the command of Vitus Bering. De l'Isle maintained that the entire area of the North Pacific explored by Bering had already been explored by the Spanish Admiral De Fonte. In Western Europe De l'Isle was supported by the French geographers Philippe Buache and. later, Robert Vogondi. and Müller's refutation of De l'Isle by the Anglo‐Irishman Arthur Dobbs. The Swiss geographer Samuel Engel also supported De l'Isle, maintaining that the Russian maps had deliberately lengthened Siberia eastward by 30° for political reasons, and specifically to discourage West European nations from attempting the Northeast Passage. 1 he German geographer A. F. Büsching then entered the fray, attacking Engel and supporting Müller. In 1776 the mysterious I.L.S. (whom the author identifies as I. I. Stafengagen of St. Petersburg) strongly rejected the accusations of De l'Isle and Engel. James Cook's voyage through Bering Strait in 1778, and his careful surveys, provided an unassailable confirmation of Müller's arguments, and the latter's position was stengthened even more by P. S. Pallas's views on Russian discoveries in the North Pacific in 1782 and by the sanctioning of Müller's position by both J. P. Forster and his son Georg Forster in 1784 and 1794, respectively.