De la Gardie
As a young adult, De la Gardie was held prisoner in the Polish–Lithuanian Commonwealth for four years, together with Carl Gyllenhielm. After being released, De la Gardie took part of the Dutch Revolt as a volunteer. In 1606–1608, De la Gardie served under the Dutch general Maurice of Nassau, Prince of Orange. Impressed with the Dutch way of waging war, De la Gardie began introducing Dutch methods into the Swedish army upon his return to the service of Sweden.