Seeing as how most everyone else is advocating generals from their own countries I will presume to do the same. Swedish military prowess has always been associated with her kings, who tended to command the army personally (especially the so called 'warrior kings' of the 17th century).
Aside from the monarchs themselves, there were two shining examples of brilliant military leadership. I am talking of two tireless Swedish generals whose joint efforts in the 30 Years War were essential to the final victory.
Johan Banér (1596-1641) was perhaps Gustavus Adolphus's most trusted and competent general, who eventually came to replace Gustav Horn as field marshal of the Swedish army following the debacle at Nördlingen in 1634. From this point on the Swedish army would not lose a single significant field battle until peace was finally signed in 1648.
Banér was a brutal man, much harsher than the late King, and did not hesitate to order the pillaging and destruction of recalcitrant towns and villages. He was also a notorious drunkard, but he happened to be one of those rare individuals who almost function better drunk than they do sober. Banér and his reorganized army won a great victory at Wittstock in 1636. The following year he carried out a masterly retreat (the famous Retreat from Torgau) from Saxony to Swedish Pommerania, evading a much superior imperial army through several devious maneuvers and feints. He won another major victory at Chemnitz in 1639.
In 1641 he attempted a surprise winter attack on the emperor and his
reichstag in Regensburg, but narrowly missed capturing the whole gathering. The French contingent, for reasons unknown, suddenly abandoned the cause, shattering all hopes of a final victory that year. Banér died (his liver probably gave up on him) during the march away from Regensburg in 1641.
Banér was a great proponent of mobile warfare and tended to leave the heavy artillery behind so that the army could march faster. While his quick maneuvers frequently surprised the enemy and won several field battles, the lack of siege artillery became a problem since fortified cities were almost impossible to take.
Lennart Torstensson (1603-1651) was another of Gustavus's disciples, whose superior use of artillery greatly contributed to the victory at Breitenfeld in 1631. He succeeded Banér as commander in chief in 1641. The Germans and Austrians came to call him 'the Snake who followed the Scorpion'. The Scorpion was of course Banér. Unlike Banér, Torstensson was originally a commoner who rose quickly in the ranks due to his talent and dedication.
When he assumed command of the army he suffered greatly from severe arthritis which often forced him to remain immobile or be carried in a palanquin. He requested to be relieved of his duty several times, since he did not consider himself 'fit for fight'. His requests were denied until 1646 to the great sorrow of the Emperor.
Torstensson was even better than Banér at getting maximum effect out of the artillery, quickly redeploying it on the battlefield and devastating the enemy ranks from unsuspected angles. He won the second battle of Breitenfeld in 1642, crushed the Danes in the war of 1643-1645 and contributed greatly to the long-delayed end of the 30YW by destroying the last great imperial army at Jankow in 1645. In recognition of his tireless efforts, he was given the title of Count in 1647. IMO he was the single greatest general Sweden has ever known, not counting the monarchs.
/Doomie
