Jacob van Heemskerk
Jacob van Heemskerk (3 March 1567 in Amsterdam – 25 April 1607 in Bay of Gibraltar) was a Dutch explorer and later admiral commanding the Dutch fleet at the Battle of Gibraltar. Brother of Cornelis van "Heemskerck" (historically correct spelling) himself a less renowned explorer of Brazil. 
Van Heemskerk's early fame arose from an attempt to discover an Arctic passage from Europe to China. Two vessels sailed from Amsterdam on 10 May 1596, under the command of van Heemskerck and Jan Rijp. Willem Barentsz accompanied Heemskerck as pilot, and Gerrit de Veer, the historian of the voyage, was on board as mate.
The masses of ice in the straits leading to the Kara Sea, and the impenetrable nature of the pack near Novaya Zemlya, had suggested the advisability of avoiding the land and, by keeping a northerly course, of seeking a passage in the open sea. They sailed northwards, and on 9 June discovered Bear Island in the Barents Sea. Continuing on the same course they sighted a mountainous snow-covered land in about 80 N. lat., soon afterwards being stopped by the polar pack ice. This important discovery was named Spitsbergen (now known as Svalbard), and was believed (incorrectly) to be a part of Greenland.
Arriving at Bear Island again on 1 July, Rijp parted company, while Heemskerck and Barents proceeded eastward, intending to pass round the northern extreme of Novaya Zemlya. On 26 August they reached Ice Haven, after rounding the northern extremity of the land. Here their vessel became anchored in ice and they wintered in a house built out of driftwood and planks from the tween decks and the deck-house of the vessel.
On 13 June they made their way in two open boats to the Lapland coast; but Barents died during the voyage, on 20 June. This was the first time that an arctic winter was successfully faced; The voyage stands in the first rank among the polar enterprises of the 16th century, and led to a flourishing whale and seal fisheries which long enriched the Netherlands.
Van Heemskerck later served as a vice admiral, protecting Dutch merchant shipping on voyages to China and the East Indies, participating in the second Dutch expedition to Indonesia. He died as a result of leg wounds caused by cannonball, shortly after the Battle of Gibraltar, an engagement in which a Spanish fleet of 21 vessels was entirely destroyed. His body was returned to Amsterdam to be buried with full honours in the old Church. His suit of armour - minus a thigh plate shattered by the fatal cannonball - is in the Rijksmuseum in Amsterdam.
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- Book name: "Journael oft daghelijcx-register van de voyagie na Rio de Plata, ghedaen met het schip ghenoemt de Silveren Werelt". Last sold earky 2015 at auction for sold for 43,000 €. A reference is made in the book of Cornelis's Famous brother (Admiral) Jacob van Heemskerck see Rare Book: Amsterdam, Cornelis Claesz. (colophon: printed by Cornelis Claesz., bookseller), 1603. Oblong 4to. 17th-century(?) gold-tooled vellum, sewn on 3 cords, each board with an arabesque centrepiece and double fillets, cloth ties, later endpapers. With a large engraving on the title-page, 5 engraved plates (1 nautical chart and 4 views, numbered , 2-3, , 5). Plate 4 sophisticated from a later edition. , 49 pp.