The Agreement between Bulgaria and the Balkan Entente was signed at Thessalonica on 31 July 1938, in duplicate. Plenipotentiaries: Georgi Kyoseivanov, president of the Council of Ministers and Bulgarian minister for foreign affairs, and Ioannis Metaxas, president of the Council of Ministers and Greek minister for foreign affairs, acting as president in office of the Permanent Council of the Balkan Entente, in the name of Greece, Romania, Turkey and Yugoslavia. LNTS vol. 196, p. 372. It is not the Balkan Pact of 9 February 1934, nor the 1919 Treaty of Neuilly, nor the Convention respecting the Thracian Frontier signed at Lausanne on 24 July 1923, whose clauses are merely waived as between the parties, nor the later Anglo-Bulgarian exchange of notes.

The preamble records that Bulgaria adheres to the policy of consolidating peace in the Balkans and desires good-neighbourly relations, and that the Entente States are animated by the same spirit towards Bulgaria. The operative part is a single paragraph: the States undertake to abstain, in their relations with one another, from any resort to force, in accordance with the non-aggression agreements to which they have severally subscribed, and agree to waive, so far as they are concerned, Part IV (Military, Naval and Air clauses) of the Treaty of Neuilly and the Convention respecting the Thracian Frontier signed at Lausanne.

The legal effect, as between the signatories, is recognition of Bulgaria’s equal rights in the matter of armament and the abandonment, as among them, of the Thracian demilitarised zone so far as those clauses bound them. The text does not list the Neuilly articles and does not set out a rearmament programme; it remains a non-use-of-force declaration plus an inter se waiver of the 1919 and 1923 peace restrictions.

Metaxas signs for all four Entente members; Bulgaria does not, by this instrument, accede to the Balkan Pact. Registration with the League of Nations followed in 1939. The United Kingdom, a signatory of Neuilly and of the Lausanne Convention, was later informed by notes, a distinct instrument from the Thessalonica agreement.

Cover: the White Tower of Thessaloniki, the city of signature; we do not claim the signing room. Wikimedia Commons, free licence.

Sources consulted: Salonika Agreement; Agreement between Bulgaria and the Balkan Entente (LNTS vol. 196).