Alexander Seaton entered the service of Christian IV of Denmark, and advanced to the rank of a captain of infantry on 8 April 1626.[1] Upon request by the Danish king, the Scottish Privy Council allowed Seaton to levy 500 Scottish soldiers on 30 June.[1]
He moved his company to Stralsund where they joined other Scots of Donald Mackay's regiment during the Battle of Stralsund (1628),[3] where he served as lieutenant colonel. He succeeded the Danish-German mercenary Heinrich Holk as Stralsund's governor.[4] During the time he was in command, the town withstood the siege of Albrecht von Wallenstein's imperial army.[4] He was succeeded as the governor in July by Alexander Leslie, a Scot in Swedish service who arrived with a contingent of Scots, Swedes and Germans.[5] Wallenstein lifted the siege on 4 August,[6] forced to accept his first check in the Thirty Years' War.[7]
Seaton did not stay with his regiment when it entered Swedish service, and instead joined the Norwegian infantry as a captain in 1628 - having left Mackay's troops as a lieutenant colonel.[1] For the next 17 years, no records of Seaton's life are known.[1]
By 1645, he had advanced to the rank of a colonel in the Norwegian army and navy again.[1] In 1645, Seaton took over eight ships of the Danish navy to fight Sweden as an admiral - the last appointment of a British in Christian IV's service.[3] With these ships, he took part in the "Norwegian response" by attacking Gothenburg (Göteborg) from the sea.[8][9] Seaton's assault took place in August,[10] just before the Treaty of Brömsebro ended the Danish-Swedish war in favour of Sweden on 13/23 August 1645.[nb 2][11][12]
The last record of Seaton is of 19 April 1649, when he was a colonel in the Norwegian army.[1] Date and place of Seaton's death are unknown, marriages are not recorded.[1]
^The battle took place between 23 and 27 September. A Danish force of 6,000 troops, commanded by Baden, Mitzlaff and Bernhard of Saxe-Weimar, landed at Heiligenhafen and was intercepted by imperial forces commanded by Schlick. Of the Danish troops, 1,000 were killed and 4,000 surrendered, only 1,000 succeeded in boarding vessels and escape with Saxe-Weimar. Among these were the surviving Scots. Guthrie (2002), p.143: "Action of Heiligenhofen [sic!]".
^In the 17th century, the Julian calendar was used in the region, which then was ten days late compared to the Gregorian calendar; 13 August - Julian, 23 August - Gregorian.
Engels, Wilhelm; Salm, Hubert, eds. (2001). Die kaiserlichen Korrespondenzen: 1646 (in German) (4 ed.). Aschendorff. ISBN978-3-402-04988-4.
Heckel, Martin (1983). Deutschland im konfessionellen Zeitalter (in German). Vandenhoeck & Ruprecht. ISBN978-3-525-33483-6.
Heitz, Gerhard; Rischer, Henning (1995). Geschichte in Daten. Mecklenburg-Vorpommern (in German). Münster-Berlin: Koehler&Amelang. ISBN978-3-7338-0195-3.
Murdoch, Steve (2000). Britain, Denmark-Norway and the House of Stuart, 1603-1660: A diplomatic and military analysis. Tuckwell Press. ISBN978-1-86232-182-3.
Steve Murdoch and Alexia Grosjean, Alexander Leslie and the Scottish Generals of the Thirty Years' War, 1618-1648 (London, 2014)