Gustavus Adolphus organized the strongest army of the early seventeenth century, courageously led his forces from the front, and earned the title of the “Father of Modern Warfare” because of his innovative skills in the tactical integration of infantry, cavalry, artillery, and logistics. His advancements in military science made Sweden the dominant Baltic power for the next one hundred years. Future commanders who studied and admired Gustavus included Napoleon I.
From the time of his son’s birth on December 9, 1594, in Stockholm, King Charles IX trained and groomed Gustavus to assume the crown. The future king learned courtly responsibilities, but his primary education focused on military leadership. At the age of only sixteen, Gustavus commanded Swedish forces against Danish invaders at East Gotland.
When Charles IX died in 1611, the Swedish Parliament was so impressed with the seventeen-year-old Gustavus that they waived the age requirement and allowed the young warrior to assume the throne. Gustavus honored their wisdom by appointing the experienced administrator Axel Oxenstierna as chancellor. The two would work in harmony over the next decades, with Oxenstierna running the government and Gustavus commanding the military.
Along with the crown, Gustavus inherited ongoing wars with Denmark, Russia, and Poland. He first turned his military might against the nearest and most threatening opponent, Denmark, and concluded a peace with them in 1613. From 1613 to 1617, Gustavus fought the Russians, achieving a victory that both acquired land for Sweden and completely cut off Russia’s access to the Baltic Sea. Eight more years of fighting between 1621 and1629 resulted in the defeat of Poland and the addition of territory to Sweden’s southern and eastern Baltic coasts.
In 1630, Gustavus, now known as “the Lion of the North,” turned his army toward Germany and entered the Thiry Years’ War against expansion efforts of the Holy Roman Empire. While the cause of Protestantism certainly influenced Gustavus, his primary reason for joining the war effort was to ensure the security of his own country’s borders. After negotiating an alliance with France, Gustavus landed his army of sixteen thousand on the coast of Pomerania and succeeded in driving the imperial forces back from the Baltic. Pushing inland, Gustavus defeated Johann Tserclaes von Tilly at the Battle of Breitenfeld, near Leipzig, on September 17, 1631.
Following that victory, Gustavus turned his army westward and occupied the rich Main and Rhine River valleys. After wintering in Mainz, Gustavus against fought with Tilly’s legions in the spring of 1632. The Bavarian battle concluded with Gustavus victorious and Tilly mortally wounded.
Tilly’s replacement, Wenzel von Wallenstein, took command of the defeated army and by fall was again prepared to do battle. After several indecisive fights around Nurenberg in September and October, Wallenstein’s imperial army and Gustavus’s forces finally became decisively engaged on November 16, 1632, at the Battle of Lutzen. In leading a cavalry attack directly into the enemy’s strength, Gustavus, a few weeks from what would have been his thirty-ninth birthday, was knocked from his horse and killed. The well-disciplined Swedish army did not retreat or surrender with the death of their leader. Instead, they rallied, charged, and gained the Lion of the North his last victory.
The same bravery and boldness that led to Gustavus’s death also symbolized his entire military career. Courage, however, played but a minor role in his successes. From policies on enlistment of the lowest-ranking soldier to the overall organization of his combat forces, Gustavus developed concepts of warfare copied for centuries.
Before Gustavus, groups of uncoordinated mercenaries composed most armies, with little overall organization or chain of command. The Lion of the North instituted permanent units, assigned a fixed chain of command, and established a philosophy of cooperation among all combatants. Instead of independent action by many different parts, the entire Swedish army now united to fight as a single team. Gustavus’s use of supply lines and bases and his integration of infantry, cavalry, and artillery enabled him to form the first truly professional army in military history.
Gustavus conscripted every young man in Sweden for a commitment of twenty years in uniform, demanding that they display high moral character and forbidding them from swearing, blasphemy, drunkenness, fornication, or looting. Their reward included regular pay and land grants. Unlike soldiers of other European armies of the times, whom the civilian population considered outcasts, Swedish soldiers were respected property owners who rented out or sharecropped their land while they were in the service.
Within the military itself Gustavus instituted permanent units with fixed organizations and chains of command. Four companies of one hundred men each formed a squadron, and three squadrons composed a brigade. Discipline, repeated drill, and actual field maneuvers constituted the army’s training.
Gustavus kept abreast of the development of new weapons and the improvement of old ones. His typical squadron contained a core of two companies of pikemen, with a company of musketeers on each flank. Gustavus experimented with various pike lengths and improved the weapons by adding steel sheathing to the wooden shafts so they could not be cut in two by enemy swordsmen. Improvements in the infantry muskets included lightening the heavy guns and training the soldiers to fire in volley rather than singly, as had been the custom. Musketeers, divided into three ranks, drilled until each rank could fire as one while the others reloaded.
Gustavus also borrowed ideas from his enemies and adapted them to his advantage. From the Germans, the Swedish cavalry learned to attack in waves, firing pistols and following with the saber. In his artillery batteries, Gustavus attempted to standardize cannon calibers to ease the resupply of ammunition. He also integrated his field artillery into his infantry and cavalry ranks, giving them direct support missions. His innovative concept of a combined arms team of mutually supporting forces remains virtually unchanged even today.
Gustavus not only influenced military practices of the future; he also provided a legacy of strength and continuity. Neither his government nor his army collapsed with his premature death. His daughter Christina assumed the throne in Sweden, and Oxenstierna continued to provide strong, fair administrative leadership to the government. In the field, Gustavus left behind efficient subordinate commanders who perpetuated his discipline and philosophy, which maintained the strength of the Swedish army for decades in the future.
Without a doubt, on the battlefield Gustavus proved himself the best commander of his age. More importantly, he developed organizations and tactics that would prevail for more than a century afterward. He truly is the “Father of Modern Warfare” and one of those few military commanders who had the respect and love of both his soldiers and citizens. As the most innovative of the top half dozen on this list, Gustavus might easily have accomplished even more and received a higher ranking if not for his early death.