Scotland and the Thirty Years' War

Scotland and the Thirty Years' War deals with the complicated involvement of the kingdom of Scotland in the Thirty Years' War of 1618–1648. Scotland and Scots were heavily entangled in both the diplomatic and military events centred on the Holy Roman Empire (roughly equating to modern Austria, Germany and the Czech Republic). There were a number of reasons for this participation.

Among these, the fate of the Scottish princess Elizabeth of Bohemia (daughter of King James VI & I) proved to be a key concern. Up to 50,000 Scottish troops arrived on the continent having been levied on warrants issued by the Privy Council and countersigned by their king, usually at periods corresponding to the participation of a particular ally in a campaign against the Habsburgs. They mostly served initially in established Scottish brigades in the Dutch Republic and Sweden which had existed before 1618. Later, specially commissioned army groups were also created in Denmark-Norway and France to facilitate further Scottish participation. Some fought for better prospects, some for kin loyalty, not a few for dynastic and confessional considerations. A few, the minority, were plain mercenaries. Although Scots participated from the start of the war until the end, formal participation by the nation was limited. Scotland formally declared war on Spain (1625–1630) and France (1627–1629), but for the most part, Scots engaged in foreign service with consent from their monarch and under warrants issued by the Privy Council but in armies commanded by their European allies.

Through such service a number of ambitious individual Scots in different European courts had a profound influence on the course of the war both conducting diplomacy and commanding entire army groups in the campaign. These included General Sir James Spens of Wormiston, Lieutenant General Patrick Ruthven, Lieutenant General James King and Field Marshal Alexander Leslie who all served in Sweden. These men were joined in Germany by an auxiliary British army under notional Swedish command and led by James, 3rd Marquis Hamilton (1631–1632).

...
Wikipedia