Gustav II Adolf (December 9 1594-November 16 1632) -- also known as Gustavus Adolphus -- was the king of Sweden from 1611 to 1632, and as such one of the major players in the Thirty Years War where he was styled as "The Lion Of The North - Savior of Protestants".
During his reign, Gustav founded the city of Gothenburg as well as a number of smaller cities.
As a general, Gustav is famous for emplying mobile artillery on the battlefield, as well as a very active tactic where attack was stressed over defense and mobility more important than in the usual linear tactic.
The king was an active participant in the battles, and was wounded several times. The war wounds led the king to adopt a flexible armour of hide instead of the customary metal cuirass, and this is what he wore in the Battle of Lützen. Gustav's armour is currently on display in Livrustkammaren in the Swedish royal palace.
Gustav was killed in the renowned Battle of Lützen where he was misled by dense fog and poor eyesight to charge into an enemy formation. After his death, his wife Maria Eleonora of Brandenburg initially kept his body, and later his heart in her bedroom for the rest her life. He now rests (including heart) in Riddarholmskyrkan in Stockholm.
see Vasa dynasty