As the Thirty Years War began to rage through Germany, Gustavus Adolphus wanted to join in the conflict, but he could not do it alone. If his troops were engaged in Germany, the undefended homeland would be attacked by Poland, or another of Sweden’s unfriendly Catholic neighbors. At this point kings were concerned primarily with gaining power for their dynasty or nation. They would gladly violate the sovereignty of a neighbor and conquer them to give a buffer against a powerful adversary. One problem that was encountered by the Protestants during this great war was that each of the nations was too concerned about its own welfare. The rulers weighed many different issues, and were not able to come to agreements to stand together. So during the first part of the war several Protestant princes were defeated one by one, by Catholics like Ferdinand, Holy Roman Emperor.

Gustavus Adolphus

Gustavus Adolphus once wrote that, “All wars in Europe hang together.” If Ferdinand was successful in creating a centralized Catholic Germany, Sweden would be in danger. So he wanted to join the war, but he would only do it under certain conditions. He would be risking his nation, and he would not do it without reward, so if the war was won he would require a German port on the Baltic sea. Sweden’s finances had been improved under his reign, but he would need money from England or France to maintain a large army. He would also need an English fleet to sail into the Baltic to protect him from Denmark, and last he would only fight if he was in command of all the armies raised. He was willing to put aside his differences with Christian of Denmark, but the rest of the Protestant powers would not agree to his requirements. So in 1625 Denmark entered into the war, and Gustavus resolved to stay out of it for the time.

Christian IV of Denmark

War with Poland

Gustavus instead turned his eyes back to Poland. He attacked in 1625. The Swedes were better provided with winter equipment, and they won some success, being treated as deliverers by the local Protestants. But when a siege of Dantzic was begun, the Swedes were unable to capture it. It could be resupplied by water, since the Swedes did not have a powerful navy to blockade. As always, Gustavus was on the front lines, twice receiving minor wounds during the siege.

Preparing for War

After two years he again turned his attention to Germany. He did not think Sweden could stay out of the engulfing conflict much longer, “for the danger is daily drawing nearer our doors.” He was farsighted enough to see that with the Catholic armies controlling Northern Germany, they were but a step away from attacking Sweden. He wrote at length to Christian of Denmark on October 21, 1627:

I have now little difficulty in discerning that the projects of the House of Hapsburg are directed against the Baltic; and that, partly by force and partly by cajolery, the United Netherlands, my own power, and finally yours are to be ousted therefrom. On the one side I understand that they intend to offer you the title of Admiral of the Roman Empire … in the same breath they have offered to help me to a safe and durable peace with Poland … nay even the Kingdom of Denmark for myself as Imperial fief, if I will ally myself with the Emperor against you. Obviously such offers are illusory, and only meant to hinder an alliance between you and me. I know well how united and diligent they are; well how disunited and slothful all those, who ought to be for us, have as yet proved themselves. As present not one of them dares to defend the other: each will look on quietly at the ruin of all. I am now putting everything aside, which can possibly hinder a swift termination of this wretched Polish business of mine. … I am not ignorant of the deplorable condition in which you stand at this moment; but I wish you had been able to call upon me for help earlier. Now we must positively during the winter concoct measures for our mutual defence, and for the defence of the Baltic.

Christian and Gustavus were able to arrange a treaty, which they signed in 1628, it was clear that Denmark would not fight Germany, as they had already been whipped by them. Sweden also signed a treaty on favorable terms with Poland on September 25, 1629. The stage was now set for war with Germany.

Having set his affairs with his neighbors in order, Gustavus was ready to face the Catholics of Germany. Around this time a Protestant Germany pamphleteer wrote of him:

Now is the time for the good towns to arm, to drive the enemy back over the Elbe. There is one at hand, who will help; who has already helped. God has raised up for us a hero, a Gideon, the like of whom lives not among men, nor in history.

When he determined that it was time to enter the Thirty Years War, Gustavus was careful to first obtain the consent of his council. He asked for the opinion of each in writing, so that their opinion would not be quelled by others.

Castle in Germany

Reasons for War

One question that historians still debate is Gustavus’ motives for engaging in the war. Many have said that he did it to defend Protestantism, and that certainly was part of it. The German Protestants had been overrun by the Catholics, and the Swedish king wished to recover their rights, and restore Protestantism to power. But there were other motives that could have played in. We have already seen where he said that the safety of Sweden was at risk. He said it again in a farewell speech to the Swedish estates:

This is a war for the defence of our Fatherland. Either we must go and find the Emperor [Ferdinand] at Stralsund [a German port of the Baltic,] or he will come and find us at Kalmar [a port city in southern Sweden.]

A victory would also increase the Swedish power, giving it control of the Baltic, and possibly even control of Germany. Was he fighting for Christianity or personal power? Did he want to restore the rights of the German princes, or make them vassals of the Swedish crown? In the end we cannot know how pure his motives and intentions were. But he did embark boldly into the struggle, emploring the help of God in his cause.

Landing in Germany

Gustavus Adolphus left Sweden for Germany on May 19, 1630, never to return. Sweden had little money and only one ally, Transylvania, which was far from his field of actions. He did not have money to pay his troops for long, and even the German princes he was coming to support were not sure they wanted his help. Gustavus wrote to Oxenstiern, his chancellor:

You say that we haven’t money to pay troops for more than four months: granted; but once let us plant our foothold sure, and God and the hour will teach us how to strengthen ourselves further.

The financial issues were arranged soon after landing, from what might seem to us from an unexpected source – France. Although France’s religion was Catholic, in foreign policy they sided with the Protestants. This was because they opposed the House of Hapsburg, the great Catholic dynasty. Cardinal Richelieu, France’s main minister, arranged to give a large amount of money to Gustavus, paying him to fight the German Hapsburg Catholics. Gustavus simply had to guarantee the right of Catholics in conquered land to practice their religion. Although Richelieu was a powerful and necessary ally for Gustavus, he would also want to be sure the Swedes did not get too powerful, as their interests just happened to coincide in this instance.


Another important event not long before Adolphus’ landing was the Edict of Restitution, which served to swing the reluctant German Protestants to his side. Up to that point, there had been important religious elements in the war, but one of the major issues was the balance of power between the emperor and the lesser German princes. But in the Edict the emperor declared that all of the church lands that had been seized by the Protestant government, or given to the Protestant religious leaders, had to be restored to the Catholic church. On hand to enforce this edict was an army of more than 130,000 men under Wallenstein, who said he would “teach the Electors manners. They must be dependent on the emperor, not the emperor on them.”  The Catholics were also allowed to try to convert the Protestants by force. In a meeting with the princes in 1630, just before Gustavus’ landing, the emperor refused to back down from this edict. For this religious and economic reason, the Protestant German princes were reluctantly pushed over to the side of Gustavus, the foreigner. Gustavus’ challenges were not only in war with the Catholics, but also from diplomacy with the Protestants.

The Thirty Years War by C. V. Wedgwood
Gustavus Adolphus and the Struggle of Protestantism for Existence by C. R. L. Fletcher

Leave a Response