Gustav Adolph was the son of Charles IX and benefited from his father's Pact of Succession in 1604 with the Swedish parliament. Charles IX died in 1611 when Gustav Adolph was sixteen years old, so a regent was appointed for the beginning of his reign. His father had fought prolonged battles with Poland-Lithuania and the regent rule mismanaged crown funds, so when Gustav Adolph took the throne, Sweden was bankrupt. It is one of his many credits as a great ruler that in just 21 years he changed the bankrupt country into a Superpower.

In modern times, Gustav Adolph was named one of the top three kings of Europe of all time (the other two being Henry VII of England and William d'Orange of Netherlands). In his own times he was known as "the Lion of the North" and the "Savior of Protestants."

Gustav Adolph was most well-known for his military genius. He not only revolutionized the art of warfare, but he was also known for his camaraderie and report with the common soldiers. He was wounded several times in battle--stabbed in the stomach and shot in the throat--and he would also die in battle.

He involved Sweden in numerous conflicts during his reign--fights with Russia over territory, renewed conflicts with Poland-Lithuania because of the failed personal union, and participation in the Thirty Year's War.