When the future King Gustav II Adolf was born in 1594, Sweden was a vast, underpopulated and poor country on the fringes of Europe, and he was not heir in line forto the throne. When he died in 1632 at the battle of Lüutzen, Sweden was one of the leading players on the European stage and Gustav Adolf himself had attained an almost mystical status which surrounds him to this day. With war and expansionism he laid the foundation for the Swedish age of greatness.

Gustav Adolf was the son of Count Duke Karl of Södermanland, and grandson of Gustav Vasa. When Gustav Adolf was a young boy, his father took power after a long conflict with his nephew Sigismund, who was at the time king of both Sweden and Poland. The dispute was centered around Swedish and Polish expansion plans which conflicted with each other, and on religion. Sigismund was Catholic and Sweden was officially Lutheran.

The prince was raised to be a genuine Renaissance Man. He was educated in both academic subjects as well as war strategy. He spoke both Swedish and German fluently and had a working knowledge of several other languages. He also became a persuasive speaker and writer, something of which he availed himself throughout his reign in order to make the nobility, the Parliament and foreign princes follow his will.

Here's an example of a letter he wrote to his brother-in-law Georg Vilhelm, Brandenburg’s Prince Regent, when when Georg Vilhelm tried to keep Brandenburg neutral during the 30 Years War:
"I will hear nothing about any neutrality. His Highness must be friend or foe. When I reach the border, he must declare himself warm or cold. This is a battle between God and the Devil. If His Highness wishes to be on the side of God, then he must side with me. Would he prefer to be with The Devil, so must he fight against me."

Gustav Adolf had inherited two a wars with Denmark from his father, one with Denmark and one with Polandand he was immediately drawn into another with Russia. Gustav Adolf spent almost his entire reign at war with Russia, Denmark, Poland and eventually even with Germany.
War demanded most of the king’s attention and he personally led the war from the front lines, as a result of which he was repeatedly wounded in battle.

However, many of these wars would not have been possible without the cooperation of the Royal Chancellor, Axel Oxenstierna, a very competent administrator. It was through him that the machinery of the state could be re-organized. The country's immense natural resources of land, copper, iron and timber could be more efficiently managed, partially in order to finance the most modern army in Europe.

When Gustav died at the age of 38, mortally wounded after leading a cavalry attack, he was known in Europe as one of the great generals of his time. He was also ruthlessly efficient at enforcing his will at the cost of great suffering. He is the only Swedish monarch who is remembered through a national Flag Day, the 6th of November, the anniversary of his death.