Bulgarians and Germans occupy Fort Rupel

On 26 May 1916 (13 May by the Julian calendar then used in Greece) a column of Bulgarian and German troops crossed the Greek border in the valley of the Struma and approached Fort Rupel. The Greek garrison opened fire and the attackers fell back, but that same day the government in Athens forbade any further resistance. The next day, 27 May, the commander of the fort handed it over to a German officer. The British chronology of the war records the occupation of the fort under 26 May, and the report of General George Milne, commander of the British forces at Salonika, under 27 May. Both dates are correct: on the first day the troops of the Central Powers entered Greece, on the second they took over the fort.

The gate of the Struma valley

The fort was built in 1914 above the gorge through which the Struma flows out of Bulgaria into Greece, a few kilometres from the border. It closed the most convenient route from Bulgaria into Greek Eastern Macedonia, with the towns of Serres, Drama and Kavala, which Bulgaria had lost to Greece after the Second Balkan War and had never stopped thinking about. Since December 1915 a neutral zone had been in force along the border, but by the spring of 1916 it was falling apart. The Allies had left the entrenched camp around Salonika and moved up towards the border, while the Bulgarians and Germans were occupying observation points just on the Greek side. On 10 May the French occupied the Greek fort of Dova Tepe west of Rupel, and the Greek garrison, in accordance with its orders, withdrew without resistance.

The Chief of the German General Staff, Erich von Falkenhayn, had since March been pressing Athens to let his troops advance deeper into Greek territory. According to the British writer George F. Abbott, who wrote on the basis of the later Greek white book, on 7 May he declared that, because the British had crossed the Struma, he must for his own security seize the Rupel pass. Prime Minister Stephanos Skouloudis tried to restrain him through the German Foreign Office. He argued that only small mounted patrols had crossed the river, and that the appearance of the Bulgarians in Macedonia would cause an outcry in Greece which Eleftherios Venizelos and the Entente would exploit. The German Foreign Office was inclined to agree with him, but Falkenhayn would not give way. On 22 May the German and Bulgarian ministers in Athens informed Skouloudis by letter that their troops would enter Greek soil in order to secure free passage through the pass. They promised respect for Greece’s integrity and sovereignty, withdrawal of the troops once the military reasons had ceased, and compensation for damage. On 23 and 24 May Skouloudis replied that he “took note” of these assurances. He did not protest, and did not make the letters public.

Shots, and an order from Athens

On the morning of 26 May a column consisting of an infantry battalion, half a squadron of cavalry and wagons appeared in front of the fort. According to Greek reports, published later in the white book, a Bulgarian officer announced that at noon a German-Bulgarian detachment, preceded by a squadron of German cavalry, would enter Greek territory. The commander of the 6th Division at Serres, General Andreas Bairas, ordered the garrison to resist anyone who advanced more than 500 metres beyond the border, in accordance with orders the war ministry had issued in May for fear of Bulgarian bands. When in the afternoon the attackers moved up the slopes of the fort, its guns fired 24 rounds, and the covering infantry also opened fire. The column fell back beyond the bridge at Kula. According to the British official history of operations in Macedonia, there were no casualties.

In Athens, however, a different decision was taken. The war ministry reinstated on the threatened sector the order of 9 March (Julian), which instructed troops to withdraw before a foreign invasion so that Greece would not be drawn into the war, and directed them merely to protest. The British official history adds that the divisional commander at Serres was forbidden to inform the French and British of anything. Late in the evening a Bulgarian officer demanded that the garrison leave the fort during the night, or it would be taken by force. On the morning of 27 May the commander of the fort, Major Ioannis Mavroudis, led his men out, and the fort was taken over by the German cavalry of Captain Thiel. The protocol of handover, drawn up in German, lists among other things two 15-centimetre guns, two 75-millimetre guns with 800 shells and 1.2 million cartridges. Skouloudis later claimed in parliament that the Greeks had removed the heavy guns and most of the equipment and had left only two field guns without breech-blocks.

The Bulgarians on the Struma

The same day the forces of the Central Powers, about 25,000 men according to the Greek government and roughly a division according to the British official history, also occupied the neighbouring fortifications and villages, the hills above the town of Demir Hisar (today Sidirokastro) and the bridges over the Struma. They halted on a line about 16 kilometres south of the border and for the time being went no further. In this way they closed the passage by which the Allies might one day have struck at Bulgaria from the Struma valley, and opened for themselves a way into Eastern Macedonia. On the evening of 28 May Skouloudis handed a protest to the ministers of Germany, Austria-Hungary and Bulgaria. In it he wrote that the incursion violated Greek neutrality and the agreement which allowed the troops of the Central Powers to come up to the border itself but not to cross it. On 30 May the German General Staff announced that German and Bulgarian troops had occupied the pass to secure themselves against an intended Entente attack, and that the weak Greek outpost had withdrawn before superior forces.

The entry of the Bulgarians, the age-old enemy, into land won in 1913 was a blow to the Greeks. The Greek minister in Rome reported that the Italians were asking what Greek assurances were worth. In France and Britain it was widely believed that Athens had colluded with the Germans. The British official history states that the Skouloudis government certainly knew of the intentions of the Central Powers and concealed them from the Allies, but that there is no evidence of collusion in any other sense. Venizelos commented: “Had we told them firmly that we would not surrender our forts to the very enemy against whom we built them, who will believe that they would have gone to war merely to occupy Rupel?” The affair of the fort deepened the National Schism in Greece and soon brought upon it a sharp reaction from the Entente.