Short Thesis
The Philippines’ territorial title rests on: (a) Spain’s colonial maps and administration (as evidence of original title and effective control); (b) Spain’s legal transfer of sovereignty to the United States by the Treaty of Paris (10 December 1898) and the supplemental 1900 Washington Convention (7 Nov. 1900) describing outlying islands; (c) international boundary delimitation with third States by treaty (notably the U.S.–U.K. Convention of 2 January 1930 delimiting the Philippines–North Borneo line); (d) progressive codification of the national territory in Philippine constitutions (1935 → 1973 → 1987), culminating in the 1987 constitutional text that embraces the archipelagic doctrine and expressly makes “the waters around, between, and connecting the islands… part of the internal waters of the Philippines”; and (e) modern international law on maritime zones (UNCLOS) and recent arbitral pronouncements (notably the 2016 PCA Award in The Republic of the Philippines v. People’s Republic of China) which define maritime entitlements and constrain historic-title claims. These elements operate together: historic titles and maps provided the factual/prehistoric basis, treaties effected legal transfers and boundary fixes, constitutions memorialized the State’s claim, and international law/decisions govern maritime entitlements and settle (or attempt to settle) disputes with other States.
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1. The 1935 Constitution (Commonwealth) — legal text and practical effect
• The 1935 Constitution defined “THE NATIONAL TERRITORY” by reference to the territories ceded to the United States by the Treaty of Paris (10 Dec. 1898) and by reference to supplemental treaties (the Washington convention 7 Nov. 1900 and later agreements). The 1935 Constitution thus anchored Philippine territorial limits expressly to earlier international instruments that effected Spanish cession to the United States.
Legal consequence: The 1935 text reflected a constitutional recognition that the State’s territorial base derived from those cessions and conventions; the constitution simply incorporated international treaty definitions into the domestic constitutional framework.
2. The 1973 Constitution
• Article I of the 1973 Constitution defines the national territory as “the Philippine archipelago, with all the islands and waters embraced therein, and all the other territories belonging to the Philippines by historic or legal title” and enumerates territorial sea, airspace, seabed, subsoil, insular shelves and submarine areas.
Legal consequence: The 1973 Charter broadened the constitutional description to include explicitly maritime and subsoil domains and recognized both historic and legal title as bases for possession — thereby implicitly accepting concepts later crystallized in UNCLOS and in the archipelagic-state doctrine.
3. The 1987 Constitution (current)
• Article I (National territory): the text contains the clearest and now-settled constitutional formulation: (i) the national territory comprises the Philippine archipelago with all islands and waters embraced therein and other territories over which the Philippines has sovereignty or jurisdiction; (ii) it enumerates terrestrial, fluvial, aerial domains, territorial sea, seabed, subsoil, insular shelves, and other submarine areas; and (iii) importantly, it states that “the waters around, between, and connecting the islands of the archipelago, regardless of their breadth and dimensions, form part of the internal waters of the Philippines.” This provision embodies the archipelagic doctrine (as later codified in UNCLOS) in the Constitution itself.
Legal consequence: The Constitution supplies a strong domestic basis for archipelagic claims and for asserting jurisdiction over maritime spaces within archipelagic baselines. It is the current constitutional foundation for any diplomatic, legislative or judicial action involving territorial sovereignty and maritime jurisdiction.
4. Treaty of Paris (10 December 1898) — Spain → United States
• Article III and related articles of the Treaty of Paris ceded the Philippine Archipelago to the United States; the Treaty (and later exchanges and protocols) served as the international instrument effecting transfer of Spanish sovereignty. The treaty came into force upon exchange of ratifications (April 1899).
Legal consequence: The Treaty of Paris is the pivotal international instrument by which sovereignty over the archipelago (as then understood) was transferred to the United States — and, as a matter of constitutional history, the 1935 Constitution referenced that treaty as the basis of the national territory.
5. Treaty (Convention) of Washington — 7 November 1900 (cession of outlying islands)
• The 7 November 1900 convention (sometimes called the “Treaty of Washington (1900)” or Convention of 1900) clarified and ceded to the United States islands lying outside the lines described in Article III of the 1898 treaty (for example, islands such as Cagayan, Sulu, Sibutu, etc.). The 1900 instrument was expressly cited in the 1935 Constitution’s territorial article.
Legal consequence: This instrument closed potential gaps left by the 1898 treaty and is part of the cluster of treaties forming the legal base of the Philippine territorial claim.
6. 1930 Convention between the United States and Great Britain (boundary w/ North Borneo)
• The Convention of 2 January 1930 between the United States and Great Britain definitively delimited the boundary between the Philippine Archipelago and the State of North Borneo (then British territory). The treaty, and subsequent exchanges of notes, fixed the outer limit between the two jurisdictions for specific purposes.
Legal consequence: Treaties between administering Powers fixed inter-State boundaries which later affect successor rights and claims (for example, issues involving North Borneo/Sabah). Such treaties remain legally relevant unless modified or abrogated by subsequent agreement.
7. Other relevant treaties, international instruments and historical maps
• UNCLOS (1982): codifies modern maritime zones (territorial sea, contiguous zone, exclusive economic zone, continental shelf) and recognizes archipelagic States and archipelagic baselines (Part IV). Philippine constitutional language on internal waters echoes UNCLOS archipelagic concepts.
• Murillo-Velarde map (1734) and other historic maps: used as historical evidence of geographic knowledge and historic connections to maritime features (e.g., the Murillo Velarde map was relied upon in Philippine submissions in the South China Sea arbitration to demonstrate historic charting).
8. Domestic and international judicial, quasi-judicial and arbitral decisions and awards
• PCA Award — The Republic of the Philippines v. People’s Republic of China (Award, 12 July 2016): the Arbitral Tribunal under Annex VII to UNCLOS ruled on the legal status of maritime features and on the inexistence (under UNCLOS) of China’s claimed historic rights within the “nine-dash line”; it clarified that historic rights inconsistent with UNCLOS do not prevail. The Award is a major, binding pronouncement in that arbitration (binding between the parties to that arbitration), and it strongly affects continental shelf/EEZ/territorial sea entitlements. China has publicly rejected the Award; enforcement remains political/diplomatic.
• Domestic courts in the Philippines have repeatedly treated territorial sovereignty and foreign-relations questions as primarily political questions (for diplomatic resolution), though the Supreme Court has considered domestic legal implications arising from treaties and legislation. (Searchable primary cases on discrete sovereign title (e.g., Sabah claims) are largely treated in executive/diplomatic contexts; there is comparatively limited domestic case law adjudicating international territorial title as a pure judicial question.)
9. Historical studies and research
• Scholarly histories and archival maps (Velarde 1734 and other charts) have been used to demonstrate continuity of naming and usage of maritime features and to establish historical links; modern historians and legal scholars use both cartographic evidence and contemporaneous administrative records when reconstructing title. The Murillo-Velarde map is frequently cited in both scholarly work and the Philippines’ legal submissions in maritime disputes.
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Synthesis — how these pieces fit in legal practice
1. Title chain: Spain’s colonial title → Treaty of Paris (1898) ± Treaty of Washington (1900) → U.S. sovereignty (1898–1946) → Philippine independence (commonwealth and republic constitutions) → Philippines as successor State with constitutionalized territorial claims. The 1930 U.S.–U.K. convention fixed parts of the external boundary vis-à-vis North Borneo.
2. Constitutional entrenchment: The 1987 Constitution codifies the archipelagic doctrine and internal-waters claim; domestic law therefore supports executive steps (baseline declarations; maritime zone claims) and provides a constitutional warrant for asserting jurisdiction.
3. UNCLOS and arbitral practice: UNCLOS provides the legal framework for maritime entitlements; the 2016 PCA Award demonstrates how UNCLOS adjudication treats "historic-rights" claims of China incompatible with UNCLOS. Thus the Philippines’ constitutional assertions must be pursued consistent with UNCLOS rules when maritime entitlements are at issue.
4. Maps and historical evidence: Cartography (e.g., Murillo-Velarde) is admissible as historical evidence but never alone dispositive; treaties and effective administration (showing State acts of authority) have decisive legal weight in international law.
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Limits / caveats
• Where interstate sovereignty claims are contested (e.g., Sabah/North Borneo, certain shoals/reefs), the legal outcome depends upon the legal instrument(s) at issue (treaties, succession doctrines, effective control, estoppel) and political/diplomatic practice; judicial resolution is possible but often precluded by the political-question character of external sovereignty.
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Primary sources and links (verified)
1. 1935 Philippine Constitution (text) — Article I (National Territory). Lawphil.
https://lawphil.net/consti/cons1935.html
2. 1973 Constitution (text) — Article I (National Territory). Lawphil / official texts.
https://lawphil.net/consti/cons1973.html
3. 1987 Constitution (text) — Article I (National Territory). Official/constitute project / ChanRobles.
https://www.constituteproject.org/constitution/Philippines_1987
https://chanrobles.com/article1.htm
4. Treaty of Peace between the United States and Spain (Treaty of Paris, 10 Dec. 1898) — text (Yale Avalon / U.S. historical documents).
https://avalon.law.yale.edu/19th_century/sp1898.asp
5. Convention / Treaty between the United States and Spain (7 Nov. 1900) — Cession of outlying islands (text and U.S. archival presentation).
https://history.state.gov/historicaldocuments/frus1900/ch105
6. Convention between the United States and Great Britain (2 Jan. 1930) — boundary between Philippine Archipelago and North Borneo (text/explanatory notes). U.S. Department of State, FRUS.
https://history.state.gov/historicaldocuments/frus1930v03/ch16
7. United Nations Convention on the Law of the Sea (UNCLOS, 1982) — full text and Part IV (archipelagic States).
https://www.un.org/depts/los/convention_agreements/texts/unclos/part4.htm
8. The South China Sea Arbitration (PCA Award), The Republic of the Philippines v. People’s Republic of China (Award, 12 July 2016) — PCA (registry) PDF and RIAA / UN collection.
https://docs.pca-cpa.org/2016/07/PH-CN-20160712-Award.pdf
9. Murillo Velarde (Velarde) map (1734) — background and institutional collection pages (Library of Congress, Philippine Cultural Center).
https://murillovelardemap.com/
https://www.loc.gov/
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Assisted by ChatGPT AI app, October 12, 2025.
