HOW DID SWEDEN'S MILITARY EVOLUTION UNDER
GUSTAVUS ADOLPHUS II CREATE BATTLEFIELD
SUCCESS
EMERZON ZUNIGA

The “Lion of the North,” Gustavus Adolphus II, created the true northern lion by
systematically reforming Sweden’s military system in the 17th century. The changes
that he made to the Swedish military led to their success on the battlefield against
larger forces, such as the Holy Roman Empire. These reforms would later
contribute to Sweden’s victory during the Thirty Years War.

An army is a group of fighters suited for battle on land; however, the attributes that
define a winning army go far beyond persons suited for battle. A successful army
needs discipline, tactical flexibility, professional officers, high morale, and esprit
de corps. During the 17th century, Swedish monarch Gustavus Adolphus II was
inspired to reform the Swedish military after being influenced by Roman tactical
manuals and the advancements of the United Provinces’ citizen army. These
reforms would later grant the Swedish military victory on the battlefield until his
death in 1632. Adolphus II recognised that that his military need to be flexible and
powerful; to do this he needed to maximize the offensive capability of his forces
and utilize the technology available. Eventually, his reforms improved his
military’s discipline and esprit de corps.
Gustavus Adolphus II created a professional soldiery and officer corps that had the
discipline and esprit de corps to win battles. Adolphus II was a religious man who
envisioned himself as the protector of Protestantism. He went to a war, the “chief
object of which [was] to free [his] oppressed brothers in faith from the clutches of
the pope.” 1 Moreover, he was the protector of important ports and trading centers
1

Robinson, Readings in European History Volume II, 207.

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along the Baltic Sea. In order to protect his religious brethren and territory he
envisioned a unified Protestant army. This contrasts with the common employment
of mercenary forces who were diverse in origin, religion, and loyal only to their
pay. To achieve the professional force that Adolphus II envisioned he expanded
Sweden's old levy system, turning it from a national draft into a more volunteer
orientated recruitment system. 2 The new system allowed professional soldiers to
develop their craft, as well as their identity through regular pay and drills; it was
also easier to establish a genuine sense of esprit de corps in a professional army.
Furthermore, Adolphus II integrated mercenary companies into the Swedish
military. He was able to hire the mercenaries for extended periods of time, as well
as holding them to the same standard as his national soldiers; this increased the
army standards, which led to an increase in discipline, and personally motivated
well-trained soldiers. Adolphus II demanded that the officer corps was properly
educated in the art of war; he also required the officers to improve their martial
prowess, and study military history and Roman tactical manuals. This change gave
officers the independence they needed to be more flexible and resilient.
The effect of the reforms can be seen in Adolphus II's confidence in his country's
military ability. In 1630, when addressing the military class, Adolphus II
proclaimed that the military spirit of the Goths of antiquity had “shone forth again
in your manly behaviour, your unfailing courage” that their descendants would
revere their “might at arms, and great conquests.” 3 Furthermore, he sought decisive
battles, suggesting that he had confidence that his army was superior. Adolphus
II’s reforms were able to showcase his army’s true effectiveness when the
professional officers were able to win the battle of Lutzen after losing their
monarch. The effects of Adolphus II's reforms are further exemplified in the
discipline, unity, and desire to fight displayed by the ethnically diverse Swedish
army which was a result of his efforts to unify the army into a cohesive fighting
force. Improving the officer professionalism, army unity, and cohesion helped win
the Swedes battles before and after Adolphus II's death; however, it was his changes
to the army’s tactical structure that made it a weapon of annihilation.
The changes Gustavus Adolphus II made to his army’s tactical structure maximized
its mobility and offensive capability. The shift to a more offensive and mobile army
was a response to the mostly defensive fighting styles of the time, which were
Tercio infantry formations and the cavalry caracole. In 1631, The Tercios at the
battle of Breitenfield were roughly fifteen hundred man, strong muskets, and pike
diamonds; it was a massive formation that was incredibly difficult to break, yet it
was very slow to maneuver and lacked offensive capability. 4 In the caracole,
cavalry acted as skirmishers, shooting and retreating in ranks to maintain regular
2

Weigly, The Age of Battles, 6.
Robinson, 208.
4
Paul, Masters of the Battlefield, 277.
3

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fire. Both these formations were hampered by the primitive quality of firearms they
employed as their primary offensive weapons and the over-complexity of their
firearm drills. Sweden was able exploit the weakness of their contemporary
opponents by reforming the military’s tactical structure. Their units were able to
increase their mobility by imitating the flexibility and unit size of the Roman cohort
which consisted of roughly five hundred men. This proved crucial in the battle of
Breitenfield. Military historian Russel Weigly notes that because of the increased
flexibility and discipline of Swedish forces they had “a capacity unparalled since
the Romans to react promptly to battlefield emergencies.” 5 Standing in stark
contrast to the Imperial Tercios ⸺ which were too slow to exploit the opportunity
created by the Saxon route ⸺ the Swedish forces could fill in the gaps of their line
faster than the Imperials because of their unit size. Adolphus II took the Swedish
army through several reforms to make it more capable on the offensive. Primarily,
the use of mass pike charges and the triple line single salvo of musket fire, the
“Swedish Salvee,” delivered shock infantry tactics. 6 The Swedish cavalry
increased its effectiveness by combining pistol fire with a direct sword drawn
cavalry charge. On both the left and right flanks of the battle of Breitenfield, the
effectiveness of Adolphus II's military reform is illustrated. On the left flank, the
use of repeated pike charges and mass volleys slowly drove the Imperials back.
While the decisive stroke of the battle was a cavalry flank that captured, and turned
the Imperial guns on Imperial Tercios and drove into the rear of the Imperial army.
Historian Paul K. Davis stated that “the victory was one of the maneuverability of
the Swedish units vs the size and weight of the tercio.” 7 He further stated:
“Conversely, it was a victory of the weight of Swedish firepower.” 8 Adolphus II
was able to effectively increase the Swedish army’s mobility and firepower by
reforming its tactical structure, giving them a decisive edge on the battlefield.
Considering the circumstances that the Swedish military had to face at Breteinfield
and Lutzen, it is remarkable that Adolphus II was able to successfully defeat armies
commanded by experienced commanders, such as Tilly, the Imperial commander
at Breteinfield having started his military career roughly 60 years prior, in 1574.
The Imperial armies of Breteinfield and Lutzen were comprised of veteran
commanders, yet both were defeated by the significantly more mobile and powerful
Swedish forces.
Gustavus Adolphus II's reforms stressed the development of professionalism,
mobility, and offensive power, which resulted in victories at Breitenfield and
Lutzen. His smaller, more flexible infantry formations could deliver more powerful
strikes, eventually leading to the Swedish army’s victory at Breitenfield. Gustavus
Adolphus II has been described as the “Lion of the North,” he was perhaps more
5

Weigly, 22.
Plant, “The Swedish System.”
7
Paul, 295.
8
Paul, 295.
6

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telling the creator of a “Northern Lion,” a quick, sharp clawed animal that was the
Swedish army. 9 The foundation that Adolphus II laid out has become the most
basic principles that define the victorious from the defeated. Professionalism,
mobility, and offensive capability are the hallmarks of an effective army. The
blitzkrieg, which specializes in fast and powerful attacks by aircrafts, tanks, and
artillery working in combination is a striking example of the changes Adolphus II
introduced to the military. This tactic soon became Swedish military’s blueprint
for success.

9

Merriman, A History of Modern Europe, 153.

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BIBLIOGRAPHY
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MERRIMAN, JOHN. A History of Modern Europe. New York, NY: Norton &
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PLANT, DAVID. “The Swedish System.” In “Pike and Shot Tactics.” BCW
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ROBINSON, JAMES HARVEY. Readings in European History Volume II. Boston:
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ZURCHER, ERIK-JAN. Fighting for a Living: A Comparative History of Military
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