<p>In 1626, the Swedish Council of the Realm recommended that their king, Gustav II Adolph (1594?1632), should "negotiate with the enemy under the helmet" in order to force Poland into accepting Swedish demands. Although Gustav Adolph's reign is known especially for its wars and not for its diplomacy, this deliberate combination of military action and diplomatic approach illustrates the true status of diplomacy in Swedish foreign policy from 1617...