John Maurice of Nassau ( ; ; ; ; 17 June 1604 – 20 December 1679), called "the Brazilian" for his fruitful period as governor of Dutch Brazil, was Count and (from 1664) Prince of Nassau-Siegen. He served as Herrenmeister (equivalent to Grand Master) of the Order of Saint John (Bailiwick of Brandenburg) from 1652 until his death in 1679.
The former residence of John Maurice in The Hague, Netherlands, is now the home of the Royal Cabinet of Paintings, named Mauritshuis, which means "Maurice House" in Dutch.
Early years in Europe
He was born in Dillenburg, and his father was John VII of Nassau-Siegen. His grandfather John VI of Nassau was the younger brother of Dutch stadtholder William the Silent of Orange, making him a grandnephew of William the Silent.
He joined the Dutch army in 1621, at a very early age. He distinguished himself in the campaigns of his cousin, the stadtholder Frederick Henry, Prince of Orange. In 1626, he became a captain. In 1629, he was involved in the capture of Den Bosch. In 1636, he conquered a fortress at Schenkenschans.
Dutch governor in Brazil
thumb|180px|left|Arms of John Maurice of Nassau, imposed upon the cross of the [[Order of Saint John (Bailiwick of Brandenburg)|Johanniterorden and encircled by the Danish Order of the Elephant]]
He was appointed as the governor of the Dutch possessions in Brazil in 1636 by the Dutch West India Company on recommendation of Frederick Henry. He landed at Recife, the port of Pernambuco and the chief stronghold of the Dutch, in January 1637. 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 dispatched 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 São Salvador, being obliged to raise the siege with the loss of many of his best officers. On receiving reinforcements in 1638, and with the co-operation of the Dutch fleet, which defeated the Spanish-Portuguese squadrons in sight of Bay of All Saints, he captured the latter city. When in 1640, Portugal recovered its independence from Spain under John II, 8th Duke of Bragança, 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; to give occupation to the host of adventurers that had assembled under his colors, he dispatched an expedition against the Spanish possessions on Plate River, while in 1643, Johan Maurits equipped the expedition of Hendrik Brouwer that attempted to establish an outpost in southern Chile. Later, he visited the conquered provinces and arranged their administration.
Life in the settlements
By this series of successful expeditions, he gradually extended the Dutch possessions from Sergipe in the south to São Luís de Maranhão in the north. With the assistance of the famous architect, Pieter Post of Haarlem, he transformed Recife by building a new town adorned with public buildings, bridges, channels, and gardens in the then Dutch style, later naming the newly reformed town Mauritsstad, after himself. He was able to pay the high construction costs from the loot of his expeditions, and from the proceeds of his estates in Germany. and Franciscus Plante's Mauritias. The painters Albert Eckhout, Frans Post, and Abraham Willaerts served as members of John Maurice's entourage.
He also established representative councils in the colony for local government, and developed Recife's transportation infrastructure. His large schemes and lavish expenditures alarmed the parsimonious directors of the West India Company, and John Maurice, refusing to retain his post unless he were given a free hand, returned to Europe in July 1644. In 1643, Nassau received an embassy from the Manikongo to strengthen the economic relations between the Kingdom of the Kongo and Dutch Brazil through the sale of slaves.
Return to Europe
thumb|200px|left|John Maurice of Nassau
Shortly after returning to Europe, John Maurice was appointed by Frederick Henry to the command of the cavalry in the Dutch army, and he took part in the campaigns of 1645 and 1646. When the war was ended by the Peace of Münster in January 1648, he accepted from Frederick William, Elector of Brandenburg (who had just married John Maurice's niece Louise) the post of governor of Cleves, Mark and Ravensberg, and later also of Minden. His success in the Rhineland was as great as it had been in Brazil, and he proved himself a most able and wise ruler.