The Thirty Years' War Bankrupts Spain and Costs It Portugal
Three decades of religious war across Europe end with Spain propping up its Habsburg cousins, losing Portugal to revolt, and formally recognizing Dutch independence
Quick facts
- War
- Thirty Years' War, 1618-1648
- Portugal revolts
- 1640, ending the Iberian Union
- Peace of Westphalia
- 1648
- Estimated deaths (war-wide)
- About 8 million
What happened
The Thirty Years' War (1618-1648) began as a religious revolt in Bohemia but grew into the last major European conflict fought along Catholic-Protestant lines, killing an estimated 8 million people across four phases of fighting. Catholic Spain backed its Habsburg relatives in the Holy Roman Empire from the start, and by the 1630s Spanish forces were fighting directly against France, even threatening Paris in 1636. The strain of financing this war on top of the ongoing Eighty Years' War against the Dutch proved too much: in 1640, Portugal revolted against its Spanish rulers, permanently ending the 1580 Iberian Union, and Spanish military efforts weakened everywhere else as a result. The war finally ended with the Peace of Westphalia in 1648, a set of treaties that also formally ended the Eighty Years' War between Spain and the Dutch Republic, recognizing Dutch independence outright.
Why it matters
Historians count the decline of the Spanish Empire among the direct results of the Peace of Westphalia, alongside Dutch independence and the loss of Portugal. A monarchy that had dominated Europe under Charles V and Philip II emerged from 1648 fighting on fewer fronts only because it had lost the fights it used to win, a decline that would culminate half a century later in the extinction of the Spanish Habsburg line itself.
How we know
World History Encyclopedia's article on the Thirty Years' War lists the decline of the Spanish Empire, Dutch independence, and Portuguese independence among the war's direct results of the 1648 Peace of Westphalia, and HISTORY.com's account independently confirms that Spain, weakened by the fighting, lost its grip over Portugal and the Dutch Republic as a consequence of the same peace settlement.
Sources
- World History Encyclopedia. Thirty Years' War · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- HISTORY.com. Thirty Years' War · Reputable sourcehistory.com · The domain "history.com" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
See something wrong? . Corrections with a source get fixed fastest.
Part of a timelineThe Spanish Empire27 events · A marriage unites two Iberian kingdoms and builds an empire that spans the globe for four centuries, financed by silver and built on conquestView all →