The Battle of Turtucaia (; , Bitka pri Tutrakan), also known as Tutrakan Epopee (, Tutrakanska epopeya) in Bulgaria, was the opening battle of the first Central Powers offensive during the Romanian Campaign of World War I. The battle lasted for five days and ended with the capture of the fortress of Turtucaia (now Tutrakan) and the surrender of its Romanian defenders.

Background By August 1916 the Central Powers found themselves in an increasingly difficult military situation – in the West the German offensive at Verdun had turned into a costly battle of attrition, in the East the Brusilov Offensive was crippling the Austro-Hungarian Army, and in the South the Italian Army was increasing the pressure on the Austro-Hungarians, while General Maurice Sarrail's Allied expeditionary force in northern Greece seemed poised for a major offensive against the Bulgarian Army.

The Romanian government asserted that the moment was right for it to fulfill the country's national ambitions by aligning itself with the Entente, and declared war on the Austro-Hungarian Empire on 27 August 1916. Three Romanian armies invaded Transylvania through the Carpathian Mountains, pushing back the much smaller Austro-Hungarian First Army. In a short time the Romanian forces occupied Orșova, Petroșani, and Brașov, and reached Sibiu on their way to the river Mureș, the main objective of the offensive.

In response the German Empire declared war on the Kingdom of Romania on 27 August, with the Kingdom of Bulgaria following suit on 1 September. On the next day the Bulgarian Third Army initiated the Central Powers' first major offensive of the campaign by invading Southern Dobruja.

Origins and state of the fortress Tutrakan was originally a Roman fort. During the reign of Emperor Diocletian (284–305) it developed into one of the largest strongholds of the Danubian limes. In the 7th century it became part of the Bulgarian Empire, until the latter was subjugated by the Ottoman Empire in the late 14th century. When the Ottoman Empire entered its period of decline, it relied on the Danube as its main defensive barrier in the Balkans. The enormous width of the river, however, proved insufficient to defend against the armies of the Russian Empire, which crossed it several times in its lower stretch during the numerous Russo-Ottoman Wars. To counter this constant threat the Ottoman military created the fortified quadrilateral Ruse–Silistra–Varna–Shumen, hoping to prevent any invaders from crossing the Balkan Mountains and threatening Istanbul. Tutrakan was situated on the northern side of the quadrilateral, on a stretch where the Danube is narrow, across from the mouth of the navigable Argeș River. This made it an excellent spot for a crossing and prompted the Ottomans to fortify it with a large garrison.

With the liberation of Bulgaria after the Russo-Turkish War (1877–1878), Tutrakan became an integral part of the country, but Bulgarian national ambitions were directed in general towards Macedonia and Thrace, and the defense of the Danube was largely neglected. As a result of the Second Balkan War, Tutrakan and the entire Southern Dobruja region were ceded to Romania in 1913, with the town being renamed to Turtucaia.

The Romanian General Staff immediately took measures to strengthen the defences of the town, designing it to serve as a bridgehead in the event of war with Bulgaria. Intensive construction work lasted for more than two years under the guidance of Belgian military engineers.Glenn E. Torrey (2003) The surrounding terrain was favorable for a bridgehead, as the heights overlooking the town form a plateau 7 to 10 kilometres wide, rising as high as 113 meters over the Danube, and being surrounded by numerous wide ravines.Petar Boychev (2009) page 4-5

The basic defense consisted of three concentric lines of trenches anchored on the river. The most forward of these were small outposts designed for surveillance. To the west, around the village of Staro Selo, the outer fortifications were of a more extensive character.

The main defensive line was constructed on the very edge of the plateau in order to keep enemy artillery away from any bridge that could be built to Turtucaia. The line stretched for almost 30 kilometers and had as its heart fifteen "centers of resistance", forts numbered from one to 15 and bearing the names of local settlements - "Turtucaia", "Staro Selo", "Daidâr", "Sarsânlar" etc. Each of these incorporated two shelters for 50 to 70 soldiers, with roofs supported by iron rails or wooden boards, on top of which a two-meter layer of earth was laid. Their profile was low, rising only about 60 centimeters, thus ensuring reasonable protection against field artillery shells. Spaced from 1.2 to 2.2 kilometers apart, the individual forts were linked by shallow trenches and machine gun nests, which were in turn connected via communication trenches to the rear of the main defensive line. The intervening spaces were further covered by rifle and machine gun positions in the flanks of the forts. The "centers of resistance" were well protected by barbed wire obstacles that reached a depth of 10 to 15 meters, but they were placed some 50 metres away from the firing line and thus could not be defended with hand grenades. A hundred meters in front of the main line the Romanians had built three rows of pitfalls and barbed wire that ran continuously from fort 15 to fort 3.Министерство на войната (1939). Most of the artillery was placed in the main defensive line, although several pieces, along with trenches and machine guns, were placed on the nearby islands of the Danube in order to support the Romanian Danube Flotilla, which was tasked with providing artillery cover on the western approaches to the fortress.

Some four kilometers from the main defensive line and three kilometers from Turtucaia itself lay the secondary defensive line of the fortress. It consisted of a single line of trenches with few prepared machine gun nests or obstacles, and no artillery at all. With their attention focused almost entirely on the main defensive line, the Romanian command largely ignored this secondary line.

For command purposes the entire area of the fortress was divided into three sectors: I (west), II (south) and III (east), also named after local villages - Staro Selo, Daidâr, and Antimova. Each of them had its own commander.

The garrison The defense of the Danube and Dobruja frontiers was entrusted to the Romanian Third Army, under the command of General Mihail Aslan, who had his headquarters in Bucharest. The fortress of Turtucaia was commanded by the head of the Romanian 17th Infantry Division, General Constantin Teodorescu, who by the beginning of the conflict had the following forces at his disposal:

17th Infantry Division (Teodorescu) 18th Infantry Brigade 36th Infantry Regiment 76th Reserve Regiment 39th Infantry Brigade 40th Infantry Regiment 79th Reserve Regiment one company of border guards one cavalry squadron four militia battalions one pioneer company

Romanian battle strength stood at 19 battalions, with over 20,000 men and 66 machine guns. Only three of the battalions were of the standing army, with the rest drawn from the reserve. A valuable asset for the garrison was the assistance of the Romanian Danube Flotilla, consisting mainly of the 2nd Monitor Division: Brătianu, Kogălniceanu and Catargiu.Spencer Tucker, Priscilla Mary Roberts, World War I: Encyclopedia, Volume 1, p. 999

General Teodorescu could rely on a large artillery park, consisting by the end of August of over 157 guns ranging in caliber from 7.5 to 21 centimeters; however, most of these were fixed guns that lacked modern, quick-firing capability. The trench artillery consisted of numerous small-caliber turret guns, while the mobile horse-drawn artillery had 23 guns, only eight of them quick-firing.Министерство на войната (1939), p.263-4 In the Western Sector the troops benefited from the guns of the Danube Flotilla. Almost all of the artillery was deployed in the main defensive line, but the fixed artillery in particular was positioned in a way that made it difficult for all the guns to concentrate their fire on a single spot. The cannon were distributed in equal quantities among the sectors, leaving no reserve at all. Compounding these difficulties was that the guns, in most cases, were firing from platforms, which meant that their position could not be shifted.

The garrison of Turtucaia was connected to Olteniţa, which lay across the Danube, by a submerged telephone cable, and to Third Army headquarters in Bucharest by a wireless telegraph station; however, it remained relatively isolated from the nearest Romanian units in Dobruja. The 9th division was almost 60 kilometres to the east in Silistra, while the 19th Division and 5th Cavalry brigade were 100 kilometres to the south-east, around Bazargic (now Dobrich). The Romanian 16th, 20th, 18th Infantry and 1st Cavalry divisions were all on the left bank of the Danube and could be used to reinforce the fortress if needed.

In general, despite some of the defence's defects, the Romanian command was convinced of the strength of the fortress, and confident in its ability to hold out against major enemy attacks. It was often referred to as "the second Verdun", or "the Verdun of the East". This comparison was not entirely without justification. Most of the major European fortresses had forts of the same type as the 15 around Turtucaia; e.g. Liège had 12, Przemyśl had 15 and Verdun itself had 23.

The attackers To protect their Danube frontier the Bulgarians had activated their Third Army as early as September 1915, giving its commander, Lieutenant General Stefan Toshev, almost a year to train and equip his troops. When Romanian intentions became clear in the middle of 1916, strengthening Third Army became a priority for the Bulgarian high command.

At the end of August the army was subordinated to Army Group Mackensen, under the overall command of Field Marshal August von Mackensen, who had transferred his headquarters from the Macedonian front for the specific purpose of coordinating the offensive against Romania. By 1 September the Third Army had concentrated 62 infantry battalions, 55 artillery batteries and 23 cavalry squadrons on the Dobruja frontier.Тошев (2007), page 18 For operations against the Turtucaia fortress General Toshev planned to use the left wing of his army, composed of the following:

4th Preslav Infantry Division (Kiselov) 1st Infantry Brigade (Ikonomov) 7th Preslav Infantry Regiment(4) 31st Varna Infantry Regiment(4) 3rd Infantry Brigade (Kmetov) 19th Shumen Infantry Regiment(4) 48th Infantry Regiment(3) 47th Infantry Regiment(2) 4th Artillery Brigade (Kukureshkov) 15th Artillery Regiment(6) 5th Artillery Regiment(6) 2nd Heavy Artillery Regiment(2) 3rd Howitzer Regiment(2) 4th Pioneer Battalion

1/1st Infantry Brigade (Nedialkov) 1st Sofia Infantry Regiment(4) 6th Turnovo Infantry Regiment(4) 4th Artillery Regiment(6) 1st Howitzer Regiment(3) 1st Pioneer Battalion

German-Bulgarian Detachment (von Hammerstein from 4 September) 1/21st German Infantry Battalion 5th March Regiment(3) 5th Opalchenie Regiment(2) 6th Uhlan Regiment 105th German Heavy Howitzer Battery 1/201st German Field Battery two not quick firing 8.7 cm batteries