Battle of the Olt Valley
The Battle of the Olt Valley consisted in a prolonged military engagement during World War I between Romanian forces on one side and Central Powers' forces (Germany and Austria-Hungary) on the other side. Within just under a month, the Central Powers had managed to conquer the -long Olt Valley from its Romanian defenders. Background
From the Turnu Roșu Pass (Rotherthurm Pass) the Olt River flows for around  in a narrow gorge, which has its southern end at Râmnicu Vâlcea. An initial Central Powers attack in the region was defeated by the Romanian Army at Sălătrucu, causing a one week-long pause in operations. The Central Powers renewed their offensive at the end of October. Initially, the Central Powers forces in the region consisted in a mixed division with mostly German leadership, but mainly Austro-Hungarian troops. After being defeated at Sălătrucu, this force was strengthened. The Central Powers forces in the region were under the command of General Konrad Krafft von Dellmensingen. Romanian forces in the region consisted in elements of the 1st Army. Commanded by General Nicolae Petala starting with 25 October, the 1st Army was placed under the command of General Paraschiv Vasilescu by early November. Vasilescu became the fourth general to command the 1st Army in two weeks. Overall course of operations
Krafft's forces consisted of one Alpine Corps division, the 73rd Austro-Hungarian Division and 2nd and 10th Austro-Hungarian Mountain Brigades. On 7 November, the 216th German Infantry Division joined this group. Opposed to this force was the I Corps of the Romanian 1st Army, consisting in the 13th and 23rd Divisions. The Alpine Corps found the going slow. The Romanian troops fought tenaciously, taking advantage of the positions they had constructed along the border before the war to slow the German progress. Troubling for Krafft was his men's tendency to rely on artillery and feel pleased with seizing one enemy position per day. In an admonition to all the forces under his command, the frustrated Krafft acknowledged that the Romanian positions were challenging, but reminded his troops that they were not fighting against French fortifications on the Western Front, urging his commanders to rely less on long artillery bombardments and more on swift infantry assaults. Moreover, the Central Powers encountered nightmarish logistical problems regarding their supplies. Although the Alpine Corps' rate of advance remained sluggish, during the first two weeks of November Krafft's units captured 80 officers and 7,000 soldiers, 12 artillery pieces and 20 machine guns. On 10 November, the Romanians dispatched the 14th Division to the region as reinforcements. Subsequently, the 13th and 23rd Divisions were merged. The struggle finally ended on 25 November, when Krafft stated that the enemy resistance in front of his corps was broken. Individual engagements

Zănoaga
On 28 October, a fresh German division took Mount Mormonta, enabling the Bavarian Guard Regiment to take Zănoaga. The Romanians had incurred over 700 combat casualties, including  15 officers and 400 soldiers captured, as well as 3 machine guns. By 1 November, the Germans had reached Titești Valley. Poiana Spinului
On 7 November, near Poiana Spinului, Romanian rifle fire claimed the life of Prince Heinrich of Bavaria, the leader of the III Battalion of the Guard Regiment, who was conducting a personal reconnaissance of the front line. His final words were: "Noblesse oblige. I do not mean that with respect to my family but rather my duty as an officer.". Perișani
At Perișani, hand-to-hand combat yielded only 2 prisoners, as the rest of the Romanians fought to the end. Cozia
Having taken Titești on 1 November, the Germans had conquered the heights on both sides of the Topologu (Mounts Fruntu and Mugele), as well as the Cozia Massif at the mouth of the Lotru. These were conquered between 6 and 9 November. The Romanians promptly counterattacked and, by 11 November, had reconquered Mount Fruntu, but it proved impossible to exploit this initial success. While the Central Powers had received reinforcements exceeding a division, the Romanians had a considerable force shifted to another sector of the front. Thus weakened, the Romanian forces had to give ground. Sălătrucu
The Bavarian Light Infantry Brigade retook Sălătrucu on 12 November. By 15 November, the German front on the western side of the Olt Valley ran just south of the village of Galotreni, and on the eastern side of the valley the front ran through the southern end of the Cozia Massif and just south of Sălătrucu, with a notable salient to the south coming from the direction of Sălătrucu itself. Râmnicu Vâlcea and Curtea de Argeș
The Romanian 7th Division arrived in the area around 20 November and brought the Germans to a halt. By 21 November, the German front ran just south of the village of Dăești, with a wide salient of little depth to the immediate east of the village. This would not last, however. On 25 November, Krafft stated that the enemy resistance in front of his corps was broken. On that very day, Râmnicu Vâlcea was finally taken. This was the southern end of the Olt Valley. The Central Powers forces in the sector had finally broken through the mountains. On 27 November, the line of the Olt River was abandoned by the Romanians, and on that same day, Krafft's forces took Curtea de Argeș. References 

Battles of the Eastern Front (World War I)
Battles of World War I involving Germany
Battles of World War I involving Romania
Battles of World War I involving Austria-Hungary
Conflicts in 1916
1916 in Romania