Wallenstein was born into a Protestant noble family in Bohemia but converted to Catholicism as a young man, and marriage to a wealthy widow made him rich. After the Bohemian revolt was crushed he bought up the confiscated estates of the rebel nobles cheaply, built a vast domain in northern Bohemia, and produced grain, weapons and cloth on it himself.
His real talent lay less in battle than in organisation and supply. In 1625 he offered the emperor a bargain: he would raise an army with his own money. To keep it fed he used a system of levying taxes and food from whatever region the army passed through. At its height the force numbered more than a hundred thousand men, supplied largely from his own estates. For the first time the emperor had an army that did not depend on the princes.
He drove the Danes back to the north and reached the Baltic, but such strength quickly bred fear. Regions in his path bore the cost whether Catholic or Protestant, and the princes demanded his dismissal. The emperor gave in to them in 1630 — just as the Swedes landed.
Recalled in 1632, he fought Gustavus Adolphus at Lützen; he withdrew from the field, but the Swedish king was killed there. Afterwards he opened peace talks with several powers without the emperor's permission, and when Ferdinand II treated this as treason and stripped him of command in 1634 he was killed by his own officers. He believed firmly in astrology, reading the future in the stars, and kept an astrologer at his side for every important decision — yet he did not escape his own end. His dramatic life was later retold in Schiller's trilogy of plays, 'Wallenstein'.