According to physicscat, the intervention of France on the side of Sweden was of immense help and at the end of the Thirty Years’ War, in the peace signed with the Empire in Osnabrück (1648), she obtained the island of Rügen, the anterior Pomerania and the duchy of Bremen thus dominating the mouth of the river routes, so important from a commercial point of view, of the Oder and Elbe. From Denmark he obtained in 1645 the strip that it occupied on the west coast (Halland) and the islands of Gotland and Ösel and in 1658 he obtained Scania, Bohuslän and the province of Trondheim with the Peace of Roskilde, cutting Norway in two., and the free passage for the Sund. But two years later the intervention of some powers induced Sweden to return some conquests to Denmark (Trondheim and Bornholm). Cristina (1654), daughter of Gustavo Adolfo, who was succeeded by Charles X (1654-60), a cousin belonging to the German Zweibrücken family. But the power acquired could not last long: too many enemies were eager for revenge, such as Denmark and Poland, while other powers arose and also opposed its control of the Baltic, such as Russia and Brandenburg. Sweden was involved in continental wars due to its alliance with France (Dutch War, 1672) and on that occasion in Fehrbellin (1675) the Swedish troops suffered a defeat by the Brandenburgers that rang like a bell. alarm of a not distant decline. Under Charles XI (1660-97) Sweden still held up well but lost Stettin (1679); but when the fifteen-year-old Charles XII (1697-1718) ascended the throne, the neighbors coalesced and attacked him: it was Denmark, Russia, Poland and Saxony. The war first saw the splendid successes of Charles XII who invaded Denmark, then defeated the Russians in Narva (1700), making the mistake of not exploiting the victory to rage against Poland and Saxony and thus giving time to Tsar Peter the Great to replenish their forces with which to Poltava (1709) destroyed the Swedish ones, forcing the king to flee to Turkey. When the latter’s intervention was resolved with a separate Russian-Turkish peace, King Charles returned to his homeland, but perished in the siege of Fredrikshald in Norway (1718), probably assassinated by his own. In 1719-21 the peaces of Stockholm and Nystad saw the loss of Karelia, England, Estonia and Livonia to Russia and part of Pomerania to Brandenburg, which had now become the kingdom of Prussia. And since the duchy of Bremen had been sold to Hanover in 1715, little remained of the Swedish conquests on the southern Baltic coast. Charles XII’s brother-in-law, Frederick I of Hesse-Kassel (1720-51), was forced to submit the decisions of the crown to the Riksdag, thus laying the foundations for a future parliamentary regime. The predominance of conservatives (hattar, Party of hats) threw Sweden into a new war with Russia, which ended with the loss of another strip of Finnish territory (Peace of Åbo, 1743). The internal conflicts between the conservatives and the liberals (mössor, Party of the caps) induced Gustavo III (1771-92), ruler of Enlightenment tendencies, to try to restore the absolute power of the king; but he was assassinated by a conspiracy of nobles. The son Gustavo IV Adolfo (1792-1808) was overwhelmed by the Napoleonic wars: allied with the Russians in 1805, he was attacked by them when in 1807 the agreement between Napoleon and Alexander took place in Tilsit. This was followed by the loss of Finland and the overthrow of the king and the crown prince and the advent of his uncle Charles XIII (1809), who the same year accepted a Constitution inspired by the French Revolution (division of powers, leaving the executive one in the hands of the king aided by responsible ministers and the legislative one at the Riksdag) to which the right to freedom of the press was added shortly after, and so on. Charles XIII in 1810 adopted as successor the French marshal J.-B. Bernadotte (d. 1844), who led the Swedish troops against France and Denmark, obtaining the personal union of Norway with Sweden in exchange for the sale of Rügen and what remained of the old conquests in Pomerania. Having become king in 1818 with the name of Charles XIV, he inaugurated a policy of peace that has lasted until today having been the governments of his successors Oscar I (1844-59), Charles XV (1859-72) and Gustavo V (1907-50) well guarded against intervening in the Crimean war (1854-56), in that of the Duchies (1864) and in the two world wars (1914-18 and 1939-45), although in the second Sweden was close first in the grip of the German-Soviet alliance and then, after 1941, in that of Hitler’s Germany, de facto master of Norway, Denmark, the Baltic states and Finland. Also the detachment of the Norwegian crown from the Swedish one, which took place in 1905 during the reign of Oscar II (1872-1907), was accomplished in an absolutely peaceful way.