Refortification
As migrant settlement continued in the summer of 1934, Robert Skinner, U.S. Ambassador to Turkey, relayed to his government the news that Turkey was "arming actively and heavily," and the General Staff of the Turkish Army was "creating a motorized army corps in Thrace." Skinner's intel was correct. Indeed, Turkey prepared for a large-scale military organization in Thrace, issuing funds and orders for a new defense buildup.
As part of an effort to create more mobile and mechanized forces in forward areas, the first tank battalion of the Turkish military was launched in Lüleburgaz in 1934, laying the foundations of armored units in Turkey. In the upper echelons, III Army Corps was the focal point of Turkey's new defense posture in Thrace. Once headquartered on the outskirts of Istanbul, III Corps was moved farther west into forward areas in Thrace with the establishment of a separate Istanbul Command. The new headquarters of the corps was Çorlu.
Turkey wanted to keep its military objectives secret. As Thrace’s fortification proceeded, officials attempted their best to keep the military activity in the region away from the gaze of domestic and international observers. However, the frantic pace of military construction, increasing force levels, and massive troop movements within earshot of the border did not escape the attention of neighboring Bulgaria, which appealed to the League of Nations on 7 March 1935 with a memorandum to protest Turkey’s fortification of Thrace.
Turkey tried to assure Bulgaria that its military precautions concerned the existing conditions in Greece, which was in a political spiral after a failed coup attempt in March. After Bulgaria retracted its appeal, Turkey immediately continued from where it left off, announcing the creation of a new fortified zone in Kırklareli in July 1935 and earmarking new funds for military construction in the fortified area and III Corps zone.
The demilitarization clauses of the Lausanne Treaty hampered Turkey's objectives in Thrace. The DMZ in the Straits area was particularly important, as the control of this waterway was a geopolitical strength and a military weakness. After some fizzled attempts, Turkish diplomats embarked on a new mission to renegotiate the regime of the Straits in April 1936. As war drums thumped nearer and louder with the Italian occupation of Ethiopia and German rearmament, the Turkish appeal found a sympathetic ear. The Montreux Convention was accepted on 20 July 1936, restoring Turkish sovereignty over the Straits and granting Turkey the right to remilitarize the DMZ area.
After the treaty’s enactment, a cabinet decree established forbidden zones in the Dardanelles and the Bosporus. Other decrees followed, authorizing the conscription of soldiers for the Straits’ remilitarization and an earlier call-up schedule for military units. Subsequently, a no-fly zone was established from Çanakkale to the Çatalca fortified zone.
As Turkey amassed more military power and control in Thrace, the ongoing reorganization and fortification also stimulated war exercises. These exercises were held to test and showcase the military’s resolve in Thrace. Although military maneuvers were supposed to rotate between the three army zones yearly, Turkey's military objectives in Thrace were a cause for an exception. Turkey held three large-scale military maneuvers in Thrace in 1936, 1937, and 1939.
The Great Maneuvers of 1937 was the most important of the three. The 1937 Maneuvers were particularly ostentatious in their display of the Turkish military’s growing strength and mechanized capabilities in Thrace. For the maneuvers, newspapers, local observers, and politicians flocked to Çorlu, as the main actor of the maneuvers, III Army Corps, was headquartered in the town. Attended by the president, prime minister, and a large crowd of foreign and domestic observers, the maneuvers ended with a military parade of about 80,000 soldiers and a convoy of military vehicles.
As the world war approached, the gloom in Europe also rendered some earlier postwar conflicts and arrangements expendable to allow for new alignments. Included in these was the renegotiation of the demilitarized status of the Thracian frontier. In agreement with other Balkan Pact members, Turkey put out feelers to Bulgaria in May 1938 to revoke the disarmament provisions of the Neuilly Treaty. After the positive Bulgarian reply, a cabinet decree authorized the Greek Prime Minister Metaxas to negotiate with Bulgaria on behalf of the Balkan Pact.
The negotiations culminated in the Salonika Agreement on 31 July 1938, whereby the disarmament clauses were mutually renounced, and the DMZs on both sides of the frontier were remilitarized. While public attention was fixated on the health of President Atatürk, Turkish troops entered the border city of Edirne to occupy the last standing DMZ in Thrace on 20 August. A cabinet decree followed to create a no-fly zone in the Kırklareli fortified zone, whose northern tip was enlarged to the border.
The mist of war grew thicker and more ominous in 1939, with the German occupation of Czechoslovakia in March, the Italian occupation of Albania in April, and the crystallization of the Pact of Steel in May. With the smell of gunpowder in the air, the Turkish government authorized the discretionary delay of the discharge of conscripts nearing the end of their active duty in Thrace on the first day of August. This was followed by a large-scale war maneuver in Thrace with 70,000 soldiers. The maneuver was intended to maintain larger forces in the region with an eye on the approaching footsteps of war.
Notwithstanding these precautions, the conclusion of the Soviet-German nonaggression pact on 23 August caught Turkey and the world by surprise and immediately provoked plans for new military road construction and the suspension of military discharges in Thrace. On 31 August, the government ordered the urgent recruitment of reserves to bring the military forces in Thrace to war strength. The next day, the war broke out.