London Protocol establishes Greek independence

Background. The Greek War of Independence (1821–1829) led to the formation of modern Greece. Following the Russo-Turkish War and the Treaty of Adrianople, negotiations among the Great Powers resulted in the London Protocol. This treaty recognized Greece as a fully sovereign state, granting it political, administrative, and commercial rights. The protocol defined the northern border from the Achelous to the Spercheios rivers, establishing the Aspropotamos–Spercheios line.

Negotiations. Prior protocols, such as the Protocol of Poros (1828) and the London Protocol of March 1829, proposed autonomous status but drew borders farther south. Kapodistrias protested limited borders. After the Treaty of Adrianople, a new round of negotiations commenced. The three powers agreed to create an independent Greek state under joint protection, concluding the protocols of 3 February 1830, which defined the Aspropotamos–Spercheios line.

Implementation. The protocol determined Greece would be a monarchy ruled by a Ruler Sovereign. The question of who would occupy the throne and the final borders were not resolved by the 1830 protocol itself: Leopold later declined the throne, the 1832 London Conference named Prince Otto of Bavaria as King, and the Treaty of Constantinople (1832) defined final borders at the Arta–Volos line, reiterated by the London Protocol of 30 August 1832. These matters were settled by the international acts of 1832, outside the 1830 protocol's own terms.