Battle during the First World War
The Battle of the Crna Bend was a significant military engagement fought between the forces of the Central Powers and the Entente in May 1917. It was part of the Allied Spring Offensive of the same year that was designed to break the stalemate on the Macedonian Front. Despite the considerable numerical and material advantage of the attackers over the defenders, the Bulgarian and German defence of the positions in the loop of the river Crna remained a formidable obstacle, which the Allies were unable to defeat not only in 1917 but until the end of the war.
Background.
With the onset of the winter of 1916, all military operations on the Macedonian Front abruptly ended. The three-month-long Monastir Offensive provided the Allies with only limited tactical successes, but it failed to knock Bulgaria out of the war by a combined attack of General Sarrail's forces and the Romanian Army. On a strategic level, the overall result of the offensive was that it managed to keep over half of the Bulgarian Army and few German units on the Macedonian Front. On the tactical level, the front line was moved in favour of the Allies by only about 50 km in the Sector of General Winkler's 11th German-Bulgarian Army. However, by the end of November, the Bulgarians and Germans were able to firmly establish themselves on the Chervena Stena – height 1248 – Hill 1050 – Dabica – Gradešnica defensive line and subsequently repel all Allied attempts to dislodge them of their positions. This brought about the stabilization of the entire front line and forced the Allies to call off the offensive altogether. The opposing sides could now regroup their exhausted forces and fortify their lines.
The strategic situation in the early spring of 1917 on all European theatres of war, except the Romanian portion of the Eastern Front, favoured implementing the Allied offensive plans adopted during the inter-allied conference of November 1916, held in Chantilly, France. These plans included an offensive on the Macedonian Front designed to support the Allied efforts on the other fronts and, if possible, defeat Bulgaria with the assistance of Russian and Romanian forces. The Bulgarians, on their part, asked the Germans to join an offensive against Salonika with six divisions, but the German High Command refused and forced the adoption of a purely defensive stance of the Central Powers forces on the Balkan Front.
Preparations.
Allied plan.
The commander of the Allied armies on the Salonika front General Sarrail, commenced preparations for the offensive as soon as he received his orders. By early spring 1917, he produced a general plan that envisaged a main attack delivered in the Serbian sector by the Serbian 2nd Army and at least two other secondary attacks – the first by the British to the east of the Vardar and the second by the Italians and French in the Crna Bend. French and Greek forces to the west of the Vardar were also to undertake aggressive action. The commander of the French Army of the East, General Paul Grossetti, informed his superior that his forces would need at least 40 days to prepare for the operations, which forced General Sarrail to set the start of the offensive for 12 April 1917. However, the harsh weather conditions soon forced him to change the starting date several times until it was determined that the main British attack should commence on 24 April and the rest on 30 April. In accordance, the British began the 2nd Battle of Doiran according to schedule but were soon forced to call off their attacks as it became clear that the rest of the Allies were not able to deliver their attacks on time. The dates were finally set for 5 May in the Crna Bend and 8 May in the Serbian and British sectors.
In the Crna Bend sector, the planned attack was assigned to the left-right of the French Army of the East – the so-called First Group of Divisions(under the command of General Georges Lebouc) and the Italian Expeditionary Force. Its primary task was to penetrate all Bulgarian and German lines in the direction of the town of Prilep and thus threaten the rear of the Bulgarian forces around the Vardar and Monastir. General Sarrail had surveyed the area and determined that the Italians and French should deliver a frontal assault against almost the entire length of the defensive line, casting doubt about the final success of the operation among the Italian and French commanders. To strengthen the Allies, Sarrail also attached a Russian infantry brigade to the Crna sector forces a few days before the attack.
Central Powers plan.
The Bulgarians and Germans were well aware of the impending Allied offensive, deciding to rely on the strength of their well-prepared fortifications, powerful artillery and machine gun fire while also placing as many troops as possible in the first lines and preparing sufficient reserves in case the Allies achieved a breakthrough and the need for powerful counterattacks arose. The task of the defenders was to preserve their positions at all costs and protect the vital lines of communication running along the Gradsko-Prilep road. By 12 February, the Germans had already launched a successful attack on Italian forces west of Hill 1050 using flamethrowers.
Italian counterattacks the next day and on 27 February were only partly successful.
Opposing forces.
Central Powers.
The Crna Bend was considered one of the most important sectors on the Macedonian Front and was always guarded by strong Bulgarian and German units. In 1917 the Central Powers forces in the area were part of the 62nd Corps of the 11th German-Bulgarian Army, both of which were commanded by German generals and staff. The first-line units assigned to the sector were the 302nd Division and the 22nd German-Bulgarian Brigade, along a 23 km front. These forces occupied a generally well-fortified line which was especially strong in the points considered crucial for the defence, such as Hill 1050, Hill 1060, Dabica etc. In such places, defence consisted of complicated networks of trenches protected by several lines of barbed wire that were usually 3–5 meters thick but sometimes reached a thickness of 10–15 meters. In addition, there were good infantry shelters connected by communication trenches. The troops were well supplied with ammunition, and their morale was high.
First-line troops
Second-line troops
Third-line troops
Total troops in the Crna Bend sector – 40 battalions, 246 machine guns, 122 guns 
Allies.
Troops of various nationalities occupied the Allied position in the Crna Bend. The western part of the sector was entrusted to the Italian Expeditionary Force, which faced parts of the 302nd division along a 10.5 km front. The sector's remainder was in the hands of the I Group of Divisions, which also had to cover a 10.5 km front line. By the beginning of May, the Allies concentrated a large force of infantry and artillery that outnumbered the Bulgarians and Germans.
First-line troops
*"34th Infantry Brigade – 6 battalions, 48 machine guns"
Second-line troops
Third-line troops
Total troops in the Crna Bend sector – 69 battalions, c. 515 machine guns, 412 guns 
Battle.
Artillery preparation.
The Allied command planned to open the battle with an artillery bombardment scheduled for 5 May 1917. On that day 91 Italian and French batteries(372 guns and heavy mortars) opened fire along the entire front of the 302nd Division and the 22nd Brigade. Due to the calm and warm weather, the entire defensive line was soon engulfed in a cloud of smoke and dust. The barrage lasted the entire day and had mixed effects, depending on the ground and strength of the fortifications it pointed at. This was the case in the sector of the 302nd division, where the Bulgarian 2/2nd Infantry Brigade was defending lines situated in a flat plain, and the shelters were not enough for all the soldiers. By contrast, the bombardment hardly fazed the German 201st Infantry Brigade, which occupied the important hills 1020 and 1050. Its infantry benefited from the rugged terrain and the excellent shelters, which were, in some cases, dug in the solid rock. The Allied artillery fire in the Bulgarian 3/7 Infantry Brigade's sector caused serious damage to part of the barbed wire and collapsed several infantry shelters. Von Reuter's troops were also exposed to the heavy bombardment and had some of their first-line trenches and barbed wire severely damaged. The Allied artillery on this part of the front was forced to pause its barrage for some time in the afternoon due to the appearance of German fighter aircraft and the destruction of one of their observation balloons. With the coming of the night, the Allied fire was significantly reduced in intensity, which gave a chance to the defenders to repair part of the inflicted damage.
At 6:00 on 6 May, the Allied artillery renewed its bombardment and continued in the same manner as the day before throughout the entire day. However, this time the Italians, French and Russians also sent patrols to check the effect of the bombardment on the Bulgarian-German lines and test the strength of the fortifications. The Bulgarians and Germans managed to hold off their attempts to close on their lines with powerful infantry and artillery fire. On this day, the Central Powers' artillery took a more active part in the battle and often engaged in counter-infantry and counter-battery work with the help of German reconnaissance planes. By the end of the day, the Allied artillery once again reduced the intensity of its
fire.
On the morning of 7 May, the Allies once again renewed their bombardment. On this day, the barrage was even harsher than the previous days, and the Italian and French guns fired more than 15,000 shells on the lines of the Bulgarian 2/2nd Infantry Brigade alone. Stronger reconnaissance patrols were dispatched but were once again held off by the Bulgarians and Germans, who answered by sending their patrols to determine whether the Allies were preparing for a significant infantry attack. The results of the three-day artillery barrage proved unsatisfactory, and General Grossetti decided that it should be continued on 8 May with the help of four observation balloons. The day for the main infantry attack was finally set for 9 May.
Overall the results of the four-day preliminary artillery bombardment proved unsatisfactory. The Allied fire did not cause severe damage to the Bulgarian and German defensive line as the greater focus of the artillery fire on some points of the line indicated the directions where the main attack was to be delivered. The defenders also used every possible moment to repair the damage to their fortifications covered by their artillery. The Allied bombardment left the Bulgarian and German artillery and its observation posts practically untouched. While the Bulgarian infantry units suffered 945 casualties during the four days of bombardment, the losses of the artillery were only ten men killed or wounded and several guns damaged or destroyed.
Infantry assault.
The Allied command set the beginning of the infantry attack for 6:30 on 9 May. As the infantry prepared, the artillery resumed its barrage with much greater vigour, engulfing the entire defensive line in a cloud of smoke and dust again. At 6:30, the Italian, French and Russian infantry moved out of their trenches, advancing against the Bulgarian and German positions along an 11 km long line.
The assault of the 35th Division.
The 35th Italian Infantry Division attacked the Bulgarian 2/2 Infantry Brigade and German 201st Infantry Brigade with its Sicilia and Ivrea infantry brigades(61st, 62nd, 161st and 162nd infantry regiments). The focal points of the assault were the powerful positions on Hill 1020 and Hill 1050. To the right, parts of the 61st regiment took advantage of the dust cloud left by the barrage, capturing a forward trench that the Bulgarians had evacuated to preserve their infantry from the Allied artillery fire. Soon after, the Bulgarian infantry responded with a counterattack that pushed back the Italians and recaptured the trench. Meanwhile, further to the right of these events, the troops of the Italian 61st regiment advanced against the Bulgarian I/9 infantry battalion but were repulsed by artillery fire. However, the regiment's 1st and 3rd battalions had greater success and managed to take control of the first-line trench of the 9th German Jäger Battalion between Hill 1020 and Hill 1050. The Italian soldiers continued advancing towards the second line of trenches, succeeding in entering it because most of the defenders were still in the trenches