Dominium maris baltici in the context of "Swedish Livonia"

Sweden, formally the Kingdom of Sweden, is a Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At 450,295 square kilometres (173,860 sq mi), Sweden is the largest Nordic country by both area and population, and is the fifth-largest country in Europe. Its capital and largest city is Stockholm. Sweden has a population of 10.6 million, and a low population density of 25.5 inhabitants per square kilometre (66/sq mi); 88% of Swedes reside in urban areas. They are mostly in the central and southern half of the country. Sweden's urban areas together cover 1.5% of its land area. Sweden has a diverse climate owing to the length of the country, which ranges from 55°N to 69°N.

Sweden has been inhabited since prehistoric times around 12,000 BC. The inhabitants emerged as the Geats (Swedish: Götar) and Swedes (Svear), who formed part of the sea-faring peoples known as the Norsemen. A unified Swedish state was established during the late 10th century. In 1397, Sweden joined Norway and Denmark to form the Scandinavian Kalmar Union, which Sweden left in 1523. When Sweden became involved in the Thirty Years' War on the Protestant side, an expansion of its territories began, forming the Swedish Empire, which remained one of the great powers of Europe until the early 18th century. During this era Sweden controlled much of the Baltic Sea. Most of the conquered territories outside the Scandinavian Peninsula were lost during the 18th and 19th centuries. The eastern half of Sweden, present-day Finland, was lost to Imperial Russia in 1809. The last war in which Sweden was directly involved was in 1814, when Sweden by military means forced Norway into a personal union, a union which lasted until 1905.

The history of Denmark as a unified kingdom began in the 8th century, but historic documents describe the geographic area and the people living there—the Danes—as early as 500 AD. These early documents include the writings of Jordanes and Procopius. With the Christianization of the Danes c. 960 AD, it is clear that there existed a kingship. King Frederik X can trace his lineage back to the Viking kings Gorm the Old and Harald Bluetooth from this time, thus making the Monarchy of Denmark the oldest in Europe. The area now known as Denmark has a rich prehistory, having been populated by several prehistoric cultures and people for about 12,000 years, since the end of the last ice age.

Denmark's history has particularly been influenced by its geographical location between the North and Baltic seas, a strategically and economically important placement between Sweden and Germany, at the center of mutual struggles for control of the Baltic Sea (dominium maris baltici). Denmark was long in disputes with Sweden over control of Skånelandene and with Germany over control of Schleswig (a Danish fief) and Holstein (a German fief).

Swedish Pomerania (Swedish: Svenska Pommern; German: Schwedisch-Pommern) was a dominion of Sweden from 1630 to 1815 on what is now the Baltic coast of Germany and Poland. Following the Polish War and the Thirty Years' War, Sweden held extensive control over the lands on the southern Baltic coast, including Pomerania and parts of Livonia and Prussia (dominium maris baltici).

Sweden, which had been present in Pomerania with a garrison at Stralsund since 1628, gained effective control of the Duchy of Pomerania with the Treaty of Stettin in 1630. At the Peace of Westphalia in 1648 and the Treaty of Stettin in 1653, Sweden received Western Pomerania (German Vorpommern), with the islands of Rügen, Usedom, and Wolin, and a strip of Farther Pomerania (Hinterpommern). The peace treaties were negotiated while the Swedish queen Christina was a minor, and the Swedish Empire was governed by members of the high aristocracy. As a consequence, Pomerania was not annexed to Sweden like the French war gains, which would have meant abolition of serfdom, as the Pomeranian peasant and shepherd regulation of 1616 was practised there in its most severe form. Instead, it remained part of the Holy Roman Empire, making the Swedish rulers Reichsfürsten (imperial princes) and leaving the nobility in full charge of the rural areas and its inhabitants. While the Swedish Pomeranian nobles were subjected to reduction when the late 17th-century kings regained political power, the provisions of the peace of Westphalia continued to prevent the pursuit of the uniformity policy in Pomerania until the Holy Roman Empire was dissolved in 1806.

The Kalmar War (1611–1613) was fought between Denmark–Norway and Sweden. Though Denmark–Norway soon gained the upper hand, it was unable to defeat Sweden entirely. The Kalmar War was the last time Denmark–Norway successfully defended its dominium maris baltici against Sweden, and it also marked the increasing influence of the two countries on Baltic politics.