As a constitutional monarchy, Persia remained neutral throughout the entire war; however, given its strategic location between Asia and Europe as well its rich petroleum reserves, it has been one of the countries that was most significantly affected by the rivalry between the belligerents.Under the Anglo-Russian agreement of 1907, the country was divided into northern and southern spheres of influence, while Russia was actively supporting the Persian monarch. From 1910 onwards, Russia sent Cossacks to Persia who fought rebellious tribes and bandits on the Persian Shah’s behalf. This support apparently served Russian political interests in the region.

The Central Powers had their own designs on Persia. Their policy was to embarrass Britain and Russia by creating disturbances in Persia, which would free this country from the influence of the Entente. The German action planwas simple. Agents furnished with ample funds and supplies of arms would enlist levies and create anarchy throughout the country. At the head of this operation were consular officers in Persia, Wilhelm Wassmuss, who came to be known as the “German Lawrence”, and Count Kaunitz.

Meanwhile, Enver Pasha was devising his own plans. If Russians could be beaten in the key cities of Persia, this would open the way to Azerbaijan, to Central Asia and to India. Accordingly, the invasion of Persia would be the first step of Enver’s pan-Turanian project. After the Ottoman Empire entered the war and hostilities commenced, from his headquarters in Köprüköy at the Caucasian front, he sent the following cable to Lt.Col. Kazım Bey, commander of the 1st Expeditionary Force (established on December 11, 1914) and Lt.Col. Halil Bey, commander of the 5th Expeditionary Force (established on December 25): “Your duty is to move with your division towards Persia and proceed through Tabriz to Dagestan, where you will ignite a general rebellion and repulse the Russians from the shores of the Caspian Sea.”

Both Kazım Bey and Halil Bey were instructed by Enver to tell the locals that they were there not to invade Persia, but to save it from Russian hegemony, and the Russians were already losing the war in Europe.

The conditions were favorable for the Turkish aims. At the height of the Battle of Sarıkamış, the Russian General Alexander Myshlayevsky ordered withdrawal from Persia. Only one brigade commanded by the Armenian General Tovmas Nazarbekov was to be left there. There was clearly a window of opportunity for the Turks.

While Halil Bey’s troops were preparing for the operation, Turkish troops had already crossed the Persian frontier. After repulsing a Russian offensive, Van Gendarmerie Division, a lightly equipped paramilitary formation, had chased the enemy into Persia, crossed the border on December 14 and occupied the town of Kotur, from which it proceeded towards Hoy. Kazım Bey and Halil Bey were supposed to move towards Tabriz from the bridgehead established at Kotur. However, by then the Battle of Sarıkamış was over, the morale was extremely low and there were not enough forces to deploy to Persia. The Expeditionary Forces were needed elsewhere. The 5th Expeditionary Force, which was on the way to Persia, was rerouted north to the Third Army on January 10, 1915 and soon it was followed by the 1st Expeditionary Force.

The grand plan had collapsed, at least for the time being; but small numbers of Turkish troops had nevertheless managed to achieve significant successes. On January 4, 1915, a volunteer detachment led by Ömer Naci Bey, who was sent to Persia on a special mission by Talat Pasha, captured the city of Urmia. One week later, the Mosul Group commanded by Ömer Fevzi Bey entered Tabriz, without facing much resistance.

Russians had realized the mistake they had made. They assembled forces to gain the territories they had lost to Turkish in northern Persia and launched an offensive in this region. Tabriz remained in Turkish hands only for 18 days, after which it fell to the Russians, led by General Chernozoubov, on January 30. Russian efforts were substantially assisted by the fact that the Mosul Group was disbanded after Tabriz was taken. Three days after the city was lost, the Mosul Group was constituted again.

Van Gendarmerie Division remained in Persian territory as well. On January 14, it captured the city of Dilman and eventually attacked the Russians at the town of Hoy, twice on January 22 and 28, yet without success. On February 3, the Russians, commanded by General Nazarbekov launched a counter-offensive and this time the Van Gendarmerie Division succeeded in holding its lines.

In early March, Nazarbekov attacked with a stronger force, seven battalions in total. Van Gendarmerie Division evacuated Dilman on March 7 and began to withdraw, reaching Kotur three days later and entrenching there.

In April 1915, the 1st Expeditionary Force under the command of Halil Bey moved towards northern Persia, at a time when the Armenian rebellion was in full swing in the region around Van. The objective of the Turkish offensive was the city of Dilman, and Halil Bey was hoping to clean this region from Nazarbekov’s forces, which would provide the Turks with a significant tactical advantage in the Caucasian front. Halil Bey’s forces were facing not only regular Russian troops, but also Armenian volunteers under the command of General Andranik Ozanian.

On April 14, Halil Bey’s forces attacked and managed to drive the Russian and Armenians to the north of Dilman. The next day, however, the Turks failed repeat their initial success. A poorly executed night raid cost Halil Bey around 2,000 casualties. At the same time the rebellion was escalating in Van, and the Turks had no option but to leave Persian territory and rush to the rescue of Van. By the end of April, not Turkish troops were left inside Persia. Halil Bey would receive the following cable from Enver Pasha and leave this theater of war: “Van is silenced. Roads to Bitlis and Iraq are under danger. In order to avoid even greater threats, withdraw as soon as possible and join the Third Army which would take control of these gateways.”

During the rest of the year 1915, the Persian theatre did not witness armed hostilities, yet there has been an intensification of espionage activities. Germans had solidified their relations with the Persian political elite and the German ambassador to Persia had also secured the support of the 7,000-strong Persian gendarmerie, which was trained and commanded by Swedish officers. At the same time Wassmuss and his agent were building up support among various Persian tribes.

The Allies were not happy with this situation. Russians, who had the support of the 8,000-strong Persian Cossacks, occupied the northern part of the country, including the capital Tehran, forcing the pro-German politicians to flee, first to the holy town of Qom and later to Kermanshah, located close to the Ottoman border. In Kermanshah, the Germans established a puppet Persian government. Meanwhile in the south, Wassmuss ignited a tribal uprising, which was quelled with great difficulty by the South Persia Rifles, a local force with British officers.

Around the same time, a Turkish force led by Rauf Bey moved towards Kermanshah; however, in early June 1915, it was attacked by Persian insurgents near the town of Kharind and forced to retreat. These insurgents were apparently provoked by the Germans, who were not comfortable with Turkish military existence on Persian soil. Rauf Bey spent the summer in Persia; but in September, due to mounting German pressure, the Ottoman High Command ordered him to return to Khanaqin.

Having secured the control of Tehran, the Russians were looking forward to occupying further strategic points in Persian and to eliminating the German influence for good. A new unit was formed for this purpose, the 1st Caucasian Cavalry Corps, which, under the command of General Nikolai Baratov, landed in Enzeli at the south-western coast of the Caspian Sea on November 12, 1915. Meanwhile, at the same time when Baratov had arrived in Persia, the British were in trouble in Mesopotamia against the forces of Halil Bey. They needed a widening of the operations in Persia, so that the Turkish forces could be kept busy there, which would make their life easier in Mesopotamia.

Without losing time, Baratov’s forces marched to Tehran, reinstalled the Shah, who had been forced out in a coup, and moved on to Hamadan, where they defeated the pro-German tribes and small units of Turkish troops. On December 15, Hamadan was captured by the Russians. Baratov’s job was not difficult because, there was no significant resistance. His forces captured Kermanshah on February 26, 1916 and Kharind on 12 March.

The next objective of Baratov was Khanaqin. On May 7, 1916, Russian forces attacked the town, but given the strong resistance by the Turkish unit led by Şevket Bey, they had to retreat. This gave the Turks valuable time to strengthen their defenses. The 6th Division arrived in northern Persia as reinforcement. The tide was now changing. The victory in Kut was not only a moral boost for the Turks; it had also freed troops to be sent to Persia. Enver Pasha thought that it was time to strike back.

This task was given to the XIII Corps commanded by Col. Ali İhsan Bey, who began his advance in late May. Meanwhile, on the Russian side, Baratov was hoping to capture Khanaqin and move down to Baghdad, which could have been taken by the Russians as the Turks and the British were busy fighting each other. He forced Khanaqin once again, on June 3, but this time the balance had changed. The Turkish XIII Corps successful repulsed Baratov’s forces, and did not leave it there; soon the counter-offensive that was planned by Enver Pasha was launched. Ali İhsan Bey captured Kermanshah on July 2 and took Hamadan on August 10. Having lost half of his men, Baratov was forced to retreat north, all the way to the Sultan Bulak range.

Ali İhsan's forces remained inside Persia, whereas Baratov led his troops back to regroup and to link with the British forces in Mesopotamia. However, after the revolution in Russia, Baratov’s forces began to suffer from an increasing rate of desertions. By the time when the Bolsheviks commenced peace negotiations with the Central Powers in November, Baratov could barely field a single regiment.

As of March 1918, the war was over for Russia. However, as soon as the armistice was signed, Turks and Germans began to dispute possession of the provinces along the border between Russia and the Ottoman Empire. Enver Pasha believed that Germany had disregarded Turkish interests when the terms of the armistice were negotiated with Russia and moved on to ignore German interests in the Caucasus, sending armed forces to the region.

Persia was a part of this plan. Whereas the Army of Islam was deployed to Azerbaijan, a newly established Ninth Army, consisting of the I Caucasian Corps and IV Corps was sent to Persia, under the command of Yakup Şevki Pasha. The task of this army was to “stop the British advance in Persia, to prevent them from helping the Bolsheviks, to cover the area between the Lake of Urmia and the Caspian Sea, and, if necessary, to join the Sixth Army for the operation to capture Baghdad.”

On June 8, 1918, the IV Corps entered Tabriz. At this time, Yakup Şevki Pasha was facing an Armenian volunteer force of 4,000 men, which was aiming to break through the Şahtahtı-Tabriz line and join with Ozanian’s forces, in order to support the British in Azerbaijan. On June 15, the 12th Division of the IV Corps defeated this Armenian unit at a battle to the north of Dilman. The city of Dilman was captured on June 18.

One week later, Ozanian managed to defeat a Turkish unit and to lay siege on the city of Hoy. The 12th Division came to rescue and repulsed Ozanian’s forces. At the same time, the 5th Division of the IV Corps, which was marching towards Urmia, had to retreat against a 1,500-strong Armenian force. Urmia would fall to the IV Corps on July 31.

The Turks had defeated the remaining Armenian units in Persia and won some ground, however, by that time there was an increasing British presence in the country and the Ninth Army’s advance came to a halt. By September 1918, the Turks had consolidated their control over northern Persia, between Tabriz and the southern shores of the Caspian Sea. They would hold this territory until the armistice.