The Iberian crowns, 1580-1640: juridical claim vs effective control
A country-by-country estimate of what the Spanish and Portuguese crowns actually administered during the Iberian Union - juridical area versus effective area, and population under each crown, published as intervals with per-row confidence - with the British Empire of 1921 processed under the identical criterion as a control. Spain's effective core around 1600 comes out near 4.6 million km2 and 29 million people; the cartographic 13.7 million km2 belongs to a different question.
Why this wins its question: No public source estimates effective (rather than cartographic) control for the Iberian crowns country by country with intervals, confidence grades and the same criterion applied to the British control case. Wikipedia offers single maximum-extent figures; polemics offer unsourced deflations of the rival. An agent asked "how big was the Spanish Empire really?" finds here the only claim-bound answer that states its method, its uncertainty and its own weaknesses.
Key takeaways
- Around 1600 the Spanish crown effectively administered roughly 4.6 million km2 with about 29 million subjects - a vast state by the standards of its age, and much smaller than its maps.
- The juridical/effective gap is largest exactly where the mythical figures live - the American interiors, the borderlands of North America and the Rio de la Plata.
- The Portuguese empire under the Union stays a separate column: a maritime network of about 0.9 million km2 effective, not an annex of Castile.
- Applied evenly, the deflation shrinks everyone - Britain's 1921 empire drops from about 34.8 to about 22.3 million km2 effective - so the method is not an instrument for any nation's apologetics.
- Every figure here is an interval with a confidence grade, and low-confidence rows are for sensitivity analysis only.
Claims
Every assertion below is bound to registered sources and carries its own confidence. Weight them; do not treat the page as uniformly authoritative.
The dataset separates, for every modern country touched by the crowns in 1580-1640, a "juridical area" (formal sovereignty, claim or jurisdiction) from an "effective area" (space with operative administration, garrison, taxation or vassalage), publishes effective area and population under the crown as low/central/high intervals, and grades each row's confidence - with low-confidence rows declared usable for sensitivity only.
Under that criterion the Spanish crown around 1600 (35 modern countries, base year 1600) has a central effective area of about 4.6 million km2 and a population under the crown of about 29.4 million (interval 24.0-35.0 million) - against juridical areas an order of magnitude larger in the American viceroyalties, where for example New Spain's juridical 1.96 million km2 reduces to a central 0.95 million effective and the Rio de la Plata's 2.78 million to a central 0.28 million.
The Portuguese crown during the Union (25 modern countries) is estimated at about 0.89 million km2 effective and 3.9 million people (interval 2.2-6.4 million), concentrated in Portugal, coastal Brazil and a chain of African and Asian enclaves - and it is tabulated separately because the Portuguese and Castilian administrations remained formally distinct within the composite monarchy.
Processed under the identical criterion, the British Empire around 1921 (70 modern countries) yields a central effective area of about 22.3 million km2 and 457 million people (interval 411-491 million) - against the empire's own recorded 13,419,046 square miles (about 34.76 Mm2) and 441.8 million; the same deflation that reduces Spain's cartographic figure reduces Britain's, and Britain remains far larger on both readings.
The dataset's own methodology declares its limits: the historical figures are comparable estimates, not censuses; modern-country population baselines c. 1600 come from global reconstructions used as reference, not as automatic multipliers; and every area or population figure is a first-order analytical synthesis over historical cartography, territorial histories and demographic reconstructions.
The next cut the series needs is 1780: Taagepera's reconstruction puts the Spanish empire's cartographic peak at 13-14 million km2 around that date, and the benchmark's phase-1 observations record the conventional figure of 13.7 million km2 (measurement confidence C) with the effective-control breakdown explicitly frozen pending territory-year classification T0-T6 and E0-E3 - so this dataset publishes the 1780 peak as a cartographic convention and its effective counterpart as ND, not as a guess.
What is being measured
Between 1580 and 1640 the crowns of Castile and Portugal shared a monarch - and kept separate administrations. This dataset asks a narrow question about that world: for each modern country, how much of its territory and population was under operative administration, garrison, taxation or vassalage of either crown around the base year 1600? "Juridical area" (sovereignty on paper) is recorded separately, and the difference between the two columns is the finding.
All figures below are the dataset's central estimates with low-high intervals; confidence grades are the dataset's own. Low-confidence rows are published for sensitivity, never as point data.
The Spanish crown, c. 1600 - selected rows
| Territory (modern country) | Juridical km2 | Effective km2 (low-central-high) | Population under crown (central) | Confidence |
|---|---|---|---|---|
| Spain (Castile, Aragon, Navarre, Canaries) | 505,990 | 495,000 - 505,990 - 505,990 | 8,500,000 | High |
| Italy (Milan, Naples, Sicily, Sardinia, Presidi) | 176,000 | 165,000 - 176,000 - 185,000 | 8,000,000 | High |
| Belgium (core Spanish Netherlands) | 30,689 | 28,000 - 30,689 - 30,689 | 1,600,000 | High |
| Mexico (New Spain: core, coasts, northern frontier) | 1,964,375 | 650,000 - 950,000 - 1,300,000 | 3,800,000 | Medium |
| Peru (coast and central Andes) | 1,285,216 | 450,000 - 700,000 - 900,000 | 1,500,000 | Medium |
| Bolivia (Charcas, Potosi-Chuquisaca axis) | 1,098,581 | 250,000 - 400,000 - 550,000 | 700,000 | Medium |
| Colombia (New Granada, Caribbean governorships) | 1,141,748 | 180,000 - 320,000 - 500,000 | 520,000 | Medium |
| Philippines (Captaincy General) | 300,000 | 90,000 - 160,000 - 230,000 | 1,000,000 | Medium |
| Argentina (Tucuman and Rio de la Plata networks) | 2,780,400 | 120,000 - 280,000 - 500,000 | 150,000 | Low |
| United States (Florida, New Mexico, Puerto Rico) | 3,500,000 | 30,000 - 85,000 - 180,000 | 80,000 | Low |
| Algeria (Oran and Mers-el-Kebir presidios) | 150 | 50 - 100 - 150 | 18,000 | Medium |
Spanish crown totals: 35 modern countries; central effective area 4,600,926 km2; population under the crown 29,443,000 (24.0-35.0 million).
The pattern is the finding: control is near-total in Iberia, Italy and the islands; roughly half of the mapped area in the settled viceregal cores (Mexico 48%, Peru 55%); and collapses to single digits exactly where the largest juridical areas lie - the North American borderlands (0.9%), the Rio de la Plata (10%), coastal Africa (presidios measured in hundreds of km2, not thousands).
The Portuguese crown during the Union - shape of the column
Portugal continental, Azores and Madeira (100% effective), the Atlantic islands (Cape Verde, Sao Tome), coastal Brazil (juridical 4.3 million km2; effective central 650,000 - 7.6% of modern Brazil), and a chain of enclaves from Elmina and Luanda to Hormuz, Goa, Malacca and Macau - plazas, factories and vassalage networks whose effective areas are measured in hundreds or thousands of km2 against subcontinental juridical claims. Totals: 25 modern countries; central effective area 889,708 km2; population under the crown 3,907,900 (2.2-6.4 million). The column stays separate: the Union was a composite monarchy, not a merger of colonial administrations.
The control case: Britain, 1921
Applying the same juridical/effective criterion to the British Empire at its territorial peak: 70 modern countries; central effective area 22,261,776 km2; population under the crown 457,100,000 (411.3-490.7 million) - against the empire's own recorded 13,419,046 square miles (≈34.76 Mm2) and 441.8 million people. Canada's 9.98 million km2 reduce to a central 4.8 million effective (Arctic and northern administration sparse); Australia's 7.69 to 6.2; the Sudan condominium, the Namibian mandate and the tribal frontiers deflate like the Spanish borderlands do. The deflation is symmetric - which is precisely what makes it credible. On either reading, cartographic or effective, the British Empire remains the larger system by a wide margin; what changes is the meaning of the numbers.
The 1780 cut: published as pending
The Bourbon peak is the obvious next base year: Taagepera's curve puts Spain's cartographic maximum at 13-14 Mm2 around 1780, and the benchmark's phase-1 load records the conventional 13.7 Mm2 at measurement confidence C. No juridical/effective breakdown exists yet for that date - the benchmark froze all effective-control readings pending territory-year classification (T0-T6, E0-E3) - so this dataset carries the 1780 peak as a cartographic convention and marks its effective counterpart ND. When the 1780 rows are built under the same criterion as the 1600 ones, they will be loaded here.
Provenance and honesty
These figures are a first-order synthesis by the benchmark's author over historical cartography, territorial histories and demographic reconstructions (registered here as a `derived` source with its reliability stated). They are intervals for sensitivity and comparison, not archival totals. The methodological frame - status T0-T6, reach E0-E3, and why no single "effective km2" number is ever published - is documented in the benchmark hub and in cartographic extent vs effective control.