NASSAU-SIEGEN, John Maurice, Prince of (nas-sow-zee'-gen), Dutch soldier, born in Delft, Holland, in 1604; died in Cleves, Germany, 29 December, 1679. From early youth he showed military talent and participated in the war against the Spaniards, especially in the siege of Breda in 1625. In 1636 he was appointed by the stadtholder, Henry of Orange, governor-general of the Dutch possessions in Brazil, and immediately after his arrival he began a campaign against the Spanish-Portuguese forces, which he defeated in repeated encounters. Believing himself strong enough to hold his own he despatched part of his forces to attack the Portuguese possessions on the coast of Africa, and continued to extend his conquests with the aid of the natives who were opposed to Spanish rule. But he received a serious check in the attack on Sao Salvador, being obliged to raise the siege with the loss of many of his best officers. On receiving re-enforcements in 1638, and with the co-operation of the Dutch fleet, which defeated the Spanish-Portuguese squadrons in sight of Bahia a Todos os Santos, he captured the latter city. When in 1640 Portugal recovered its independence from Spain under the Duke of Braganza, the Prince of Nassau-Siegen, anticipating an alliance with the latter, and believing that a treaty of peace with Portugal would leave Holland in possession of the conquered territory, hastened his operations, and, to give occupation to the host of adventurers that had assembled under his colors, he despatched an expedition against the Spanish possessions on Plate river and Chili, meanwhile visiting the conquered provinces and arranging their administration. In 1643 he was recalled and returned with great riches to Holland, where he was made general-in-chief of cavalry and governor of the fortress of Wesel. The Elector of Brandenburg made him afterward grand master of the Teutonic order and governor of Cleves, where he established magnificent gardens. In the Paris library there are two folio volumes containing a fine collection of colored prints of Brazilian animals and plants, which were executed by order of the prince, and accompanied with a short explanation by him. Gaspar van Baerle describes the prince's government in America in his " Return in Brazilia gestarum Historia" (Amsterdam, 1647).