Formed soon after the 8th and 9th Battalions in September 1914, the 10th were sent to France a year later but, instead of going into the trenches, were suddenly diverted via Marseilles to Salonika. Their move had been precipitated in mid-October 1915 by Bulgaria making an alliance with Germany and Austria. At the request of Greece, Britain and France therefore sent troops to Macedonia to counter any Bulgarian aggression there. The 10th arrived in Salonika on 21st November 1915.
In July 1916, after some months spent on garrison duties, the 10th Devons arrived in the front line near Doiran close to the Bulgarian position at Petit Couronne. Here in August the Bulgarians attacked but were repulsed by A Company, whose rapid fire inflicted heavy casualties. By the end of September nearly a third of the 10th had been admitted to hospital suffering from malaria or dysentery. Nonetheless, the Battalion remained in these positions for several months, patrolling and occasionally skirmishing with their opponents.
To invade and neutralise Bulgaria the Allies would have to breach the Bulgar front line. On the night of 10th February 1917 the 10th attempted this by launching an unsuccessful attack on Petit Couronne, perched high above a rocky ravine. Meeting fierce resistance, running out of ammunition and having lost 150 casualties, they were forced to withdraw. They had taken thirty prisoners and inflicted heavier casualties on the Bulgarians, but the position remained untaken. Two months later the attack on Petit Couronne was renewed from a different angle. A gap was blown in the enemy wire and the Devons stormed through but they were the only British troops to have taken and held part of the enemy front line. Again, they were ordered to retreat. This time the Devons’ losses among the 650 men who had attacked Petit Couronne were 450 killed, wounded or missing.
The rest of 1917 and the spring and summer of 1918 were spent holding part of the front line and patrolling, awaiting an Allied offensive which finally began on 14th September 1918. By the 18th, once the Serbs had taken Doiran and Petit Couronne had finally fallen, it was clear that the Bulgarians were in retreat. On the 28th the 10th Devons crossed into Bulgaria and received news that the Bulgarians were suing for peace. Hostilities ceased at noon on 29th September. The Turkish enemy, however, remained and the Devons set out towards the Turkish border. While plans were being made for a brigade attack on the Turkish positions near Adrianople the Turkish capitulation was announced.
On 1st December 1918 the 10th Devons marched as sole representatives of the British Army through the streets of Bucharest to mark the entry of the pro-Allied Romanian King and Queen into their country’s recently liberated capital. The Battalion’s long and uncomfortable campaign in Macedonia had earned them the battle honours Macedonia 1915-18 and Doiran 1917-18 and cost them 188 killed and several times that number wounded and sick.