The establishment of adominium maris baltici[nb 1] ("Baltic Sea dominion") was one of the primary political aims of theDanish andSwedish kingdoms in thelate medieval andearly modern eras.[1][2] Throughout theNorthern Wars the Danish and Swedish navies played a secondary role, as thedominium was contested through control of key coasts by land warfare.[3]
The term, which is commonly used in historiography, was probably coined in 1563 by theKing of Poland,Sigismund II Augustus, referring to the hegemonial ambitions of his Swedish adversaries in theLivonian War.[4] The first written reference stems from theDutch-Swedish treaty of 5 (O.S.) / 15 (N.S.) April 1614, concluded inThe Hague.[4][nb 2]
Several European powers regarded theBaltic Sea as of vital importance.[5] It served as a source of important materials and as a growing market for many commodities.[5] So large did the importance of the region loom that it became of interest even to powers that did not have direct access to it, such asAustria andFrance.[5] For several centuries, Sweden and Denmark would attempt to gain total control of the sea, a policy which other local and international powers opposed.[2][5] Historians have described the control of the Baltic as one of the main goals of Denmark's and Sweden's policies.[6][7][8][9]
The Scandinavian (Nordic) powers, who sensed opportunity in the power vacuum created by the weak or non-existent naval power of theHoly Roman Empire andPoland–Lithuania, adopted expansionist policies which fostered conflict over the Baltic.[2][10] Denmark and Sweden used their control of parts of the Baltic to fuel their militaries.[2] Each claimed the Baltic as their own, and promised to protect foreign shipping.[2] While the Nordic powers vied with one another over control, they both agreed that it should be the domain of one of them, not of an "outsider" like Poland or Russia.[4] The Scandinavian powers tried to prevent the rise of their opposition through diplomatic treaties, which forbade other powers like Russia or Germany to build navies, and through military actions, whether targeting opponent naval forces, or through taking control of the Baltic ports.[4] In one of the most notable actions to retain its monopoly over the Baltic, Denmark in 1637 destroyed, without declaration of war, the nascentPolish–Lithuanian Commonwealth Navy.[4]
The numerous wars fought for thedominium maris baltici are often collectively referred to as theNorthern Wars.[11] Initially Denmark had the upper hand, but eventually it lost ground to Sweden.[12] Neither Denmark nor Sweden managed to realize thorough military and economic control of the Baltic, though Sweden duringits time as an empire came closest to that aim before theGreat Northern War of 1700–1721.[5]
Historiography uses the termdominium maris baltici either in a narrower sense as a new Swedish concept of the Early Modern era, closely tied to theSwedish Empire,[13] or in a wider sense including the preceding Danish hegemony in the southern Baltic Sea.[14]
Denmark had subdued the southern Baltic coast from Holstein to Pomerania in the 12th century, but lost control in the 13th century after being defeated by German and Hanse forces in theBattle of Bornhöved (1227), retaining just theprincipality of Rügen. Thereafter, theHanseatic League became the dominant economic power in the Baltic Sea.[14]Robert Bohn creditsValdemar IV "Atterdag" of Denmark (reigned 1340–1375) as the first Danish king to pursue a policy of establishing a Danishdominium maris baltici, aiming at adding to Denmark's naval dominance and economical hegemony at the expense of the Hanseatic League.[14] To achieve this aim, Valdemar soldDanish Estonia to theTeutonic Order state in 1346, consolidating his finances and raising an army from the revenue.[14] After initial territorial gains, Valdemarconquered the Hanseatic town ofVisby (Gotland) in 1361, resulting in a war decided in favour of the League in thepeace of Stralsund in 1370, which marked the climax of Hanseatic power.[15]
Atterdag's daughter andde facto successor,Lady Margaret, managed to concentrate the crowns of Denmark,Norway andSweden in herCopenhagen-centeredKalmar Union from 1397.[16] In 1429, Kalmar kingEric of Pomerania started to raise theSound Dues from merchants entering or leaving the Baltic Sea, allowing the Copenhagen court to benefit from the Baltic Sea trade profitswithout engaging in economic adventures itself.[17] The Sound Dues, imposed until 1857 and constituting a primary source of income for the Royal treasury, quickly became a contentious issue, which brought Denmark into conflict with the Hanseatic League and the neighboring powers.[18]
After the break-up of the Kalmar Union in the early 16th-century, theKingdom of Sweden becameDenmark–Norway's primary rival for hegemony in the Baltic Sea.Christian IV of Denmark's victory in theKalmar War in 1613 marked the last instance of a successful defense of a Danishdominium maris baltici against Sweden; subsequent wars ended in Sweden's favor.[19] The period of Danish intervention in theThirty Years' War of 1618–1648 (Kejserkrigen of 1625–1629) is also considered[by whom?] part of the wars for thedominium maris baltici[20]—in this war, however, the opponent was not the Swedish king, but the ambitiousHoly Roman EmperorFerdinand II, who temporarily planned to establish the Empire as a naval power in the Baltic. He assigned this task toAlbrecht von Wallenstein, leading to a concerted action by Denmark and Sweden in thedefense of Stralsund. The Danish defeat in theBattle of Wolgast (1628) and the subsequentTreaty of Lübeck in 1629, however, removed Denmark from the battlefield.[21]
After Sweden had left the Kalmar Union in 1523, she became Denmark's major rival for thedominium maris baltici. The first war ascribed to this conflict is theNorthern Seven Years' War (1563–1570, associated with theLivonian War), which between 1611 and 1613 followed the above-mentionedKalmar War.[20] Major Swedish successes followed the capture ofRiga in 1621[22] and theSwedish landing in Pomerania in 1630.[21] The gains in theTorstenson War,[20] a theater of theThirty Years' War, humiliated Denmark, and the subsequentPeace of Westphalia confirmed Sweden's status as a European great power (stormaktstiden). Swedish control of the Baltic was not thorough, however, since themaritime powers, especially theDutch Republic, continued to be economically and militarily present and pursued theirbalance of power policy also in respect to Denmark and Sweden. TheSecond Northern War,[20] theScanian War[20] and thefirst stage of theGreat Northern War[20] left Sweden'sdominium maris baltici intact, yet it was finally ended by theTreaty of Nystad in 1721. Sweden had sought to secure herdominium maris baltici by turning many towns (e.g. Riga, Narva, Wismar) into fortresses, often under the aegis ofErik Dahlbergh.[23] Since the Thirty Years' War, Sweden collected customs (Licenten) from merchant vessels on the Baltic Sea, in Swedish as well as in non-Swedish ports.[24] These customs were calculated as a certain percentage of the value of transported goods, and once payment took place in any port, the respective receipt was valid for the wholedominium maris baltici.[25]
| Regions | Major ports | Notes |
|---|---|---|
| Scania | Helsingborg | Scania,along with the adjacent provinces, was ceded to Sweden by Denmark in theTreaty of Roskilde in 1658, during theSecond Northern War. |
| Malmö (Malmø) | ||
| Ystad | ||
| Blekinge | Karlskrona | Karlskrona founded in 1680 as primary Swedish naval base after Blekinge was ceded to Sweden byDenmark in theTreaty of Roskilde in 1658, during theSecond Northern War. |
| Mecklenburg | Wismar | Swedish occupation and customs since 1632, Swedish dominion after thePeace of Westphalia, Danish occupation in 1675 (Scanian War),[26] restored to Sweden in thePeace of Lund (1679),[26] thereafter Swedish fortress,[26] occupied by Danish, Hanoveranian and Brandenburgian forces during theGreat Northern War,[27] restored to Sweden under the caveat that the fortifications were razed,[27] reduced in significance and pawned by Sweden toMecklenburg-Schwerin in 1803[28] |
| Rostock | Warnemünde, controlling the entry to the Rostock port, was ceded to Sweden in 1632 (Thirty Years' War), fortified and served to raise customs until 1714[29] | |
| Pomerania | Stralsund | Swedish garrison since thebattle of Stralsund (1628) (Thirty Years' War), remained inSwedish Pomerania until 1815 |
| Greifswald | Nominally under Swedish military control after theTreaty of Stettin (1630), conquered in 1631 (Thirty Years' War), remained inSwedish Pomerania until 1815 | |
| Stettin (Szczecin) | Controlled trade on theOder, under Swedish military control after theTreaty of Stettin (1630), during theThirty Years' War), remained inSwedish Pomerania until the 1720Treaty of Stockholm (Great Northern War) | |
| Kolberg (Kołobrzeg) | Most important of the relatively minorFarther Pomeranian ports, which all came under Swedish military control following theTreaty of Stettin (1630). While ceded to theBrandenburg-PrussianProvince of Pomerania (1653–1815) in theTreaty of Stettin (1653), Sweden retained a share of the customs. | |
| Danzig (Gdańsk) | Controlled trade on theVistula, principal port of thePolish–Lithuanian Commonwealth (Royal Prussia province). Major trading point for the Dutch merchant fleets. Swedish customs following theTruce of Altmark (1629). Navy destroyed. | |
| Prussia | Elbing (Elbląg) | A port in the Polish–Lithuanian Commonwealth (Royal Prussia province). Swedish occupation and customs during and after thePolish–Swedish War (1626–29), concluded by theTruce of Altmark (1629). Again during theSecond Northern War, when it was also the site of a Dutch–Swedish agreement on Dutch rights in the Baltic Sea (Treaty of Elbing, 1659). Swedish troops cleared the city in 1660, following theTreaty of Bromberg. |
| Königsberg (Królewiec, Kaliningrad) | A port of theDuchy of Prussia, vassal of Poland. Swedish customs following theTruce of Altmark (1629), Swedish vassalage of theDuchy of Prussia by theTreaty of Königsberg (1656), succeeded by the Prusso-Swedishalliance of Marienburg and its break-up in theTreaty of Bromberg, all during theSecond Northern War | |
| Pillau (Piława, Baltisk) | A port of theDuchy of Prussia, vassal of Poland. Swedish occupation and customs during and after thePolish–Swedish War (1626–29), concluded by theTruce of Altmark (1629), Swedish vassalage of theDuchy of Prussia by theTreaty of Königsberg (1656), succeeded by the Prusso-Swedishalliance of Marienburg and its break-up in theTreaty of Bromberg, all during theSecond Northern War | |
| Livonia | Riga (Ryga) | Controlled trade on theDüna (Daugava) river (Livonian hinterland, Belarus and Russia). Under the Polish–Lithuanian Commonwealth control until Swedish conquest in 1621, remained inSwedish Livonia until thecapitulation of Estonia and Livonia in 1710, formalized in theTreaty of Nystad in 1721. |
| Pernau (Parnawa, Pärnu) | Under the Polish–Lithuanian Commonwealth control until 1617; inSwedish Livonia until thecapitulation of Estonia and Livonia in 1710, formalized in theTreaty of Nystad in 1721. | |
| Estonia andIngermanland | Reval (Tallinn) | Subordinated itself to Sweden in 1561 (Livonian War), remained inSwedish Estonia until thecapitulation of Estonia and Livonia in 1710, formalized in theTreaty of Nystad in 1721. |
| Narva | Important hub for Russian trade. Russian control from 1558 to 1581, Swedish afterward, retaken by the Russians in 1704 | |
| Islands | Notes | |
| Gotland (Gothland) | Ceded to Sweden by Denmark in theSecond Treaty of Brömsebro (1645), after theTorstenson War | |
| Ösel (Øsel, Saaremaa) | ceded to Sweden by Denmark in theSecond Treaty of Brömsebro (1645), after theTorstenson War | |
| Bornholm | Temporarily conquered by Sweden in 1645 (Torstenson War), ceded to Sweden by Denmark in theTreaty of Roskilde (1658), during theSecond Northern War, restored to Denmark by theTreaty of Copenhagen (1660) | |
| Rügen (Rygen, Rugen) | Under Swedish military control after theTreaty of Stettin (1630) (Thirty Years' War), remained inSwedish Pomerania until 1815 | |
| Straits | Notes | |
| Öresund (Øresund, "The Sound") | Entrance to the Baltic Sea from the North Sea, both coasts under Danish control until 1658, Sweden exempted from the DanishSound Dues after theSecond Treaty of Brömsebro (1645) (Torstenson War), eastern coast Swedish since theTreaty of Roskilde (1658, see Scania entry) | |
The failure of the Scandinavian powers to take control of the Baltic, and steadfast refusal of other powers – local and international – to recognize their claims, is seen as one of the factors that led to the development of the "freedom of the seas" principle ininternational law.[5]