The Brusilov offensive, also known as the "June advance", of June to September 1916 was the Russian Empire's greatest feat of arms during World War I, and among the most lethal offensives in world history. The historian Graydon Tunstall called the Brusilov offensive the worst crisis of World War I for Austria-Hungary and the Triple Entente's greatest victory, but it came at a tremendous loss of life. The heavy casualties eliminated the offensive power of the Imperial Russian Army and contributed to Russia's collapse the next year.
Franz Xaver Josef Conrad von Hötzendorf, sometimes anglicised as Hoetzendorf, was an Austrian general who played a central role in World War I. He served as K.u.k. Feldmarschall and Chief of the General Staff of the military of the Austro-Hungarian Army and Navy from 1906 to 1917. He was in charge during the July Crisis of 1914 that caused World War I.
General Erich Georg Sebastian Anton von Falkenhayn was the second Chief of the German General Staff of the First World War from September 1914 until 29 August 1916. Falkenhayn was removed on 29 August 1916 after the failure of his offensive strategy in the west at the Battle of Verdun, the opening of the Battle of the Somme, the Brusilov Offensive and the Romanian entry into the war. Having planned to win the war before 1917, the German army was reduced to hanging on.
Archduke Eugen Ferdinand Pius Bernhard Felix Maria of Austria-Teschen was an Archduke of Austria and a Prince of Hungary and Bohemia. He was the last Grand Master of the Teutonic Knights from the Habsburg dynasty.
Johannes "Hans" Friedrich Leopold von Seeckt was a German military officer who served as Chief of Staff to August von Mackensen and was a central figure in planning the victories Mackensen achieved for Germany in the east during the First World War.
The Eastern Front or Eastern Theater of World War I was a theater of operations that encompassed at its greatest extent the entire frontier between Russia and Romania on one side and Austria-Hungary, Bulgaria, the Ottoman Empire, and Germany on the other. It ranged from the Baltic Sea in the north to the Black Sea in the south, involved most of Eastern Europe, and stretched deep into Central Europe. The term contrasts with the Western Front, which was being fought in Belgium and France.
The 1st Army was a field army-level command in the ground forces of Austria-Hungary during World War I. The army fought in Galicia and Russian Poland in 1914–15 before being briefly dissolved in the summer of 1916. Shortly afterwards, it was reformed and sent to fight in the Romanian Campaign for the next two years. The 1st Army was demobilized in April 1918 due to its heavy losses, following Romania's surrender.
Viktor Julius Ignaz Ferdinand Graf Dankl von Kraśnik was a highly decorated Austro-Hungarian officer who reached the pinnacle of his service during World War I with promotion to the rare rank of Colonel General (Generaloberst). His successful career met an abrupt end in 1916 due to both his performance on the Italian front and health issues. After the war, he would be a vocal apologist for both his country's war record and the dethroned Habsburg monarchy.
The Kingdom of Romania was neutral for the first two years of World War I, entering on the side of the Allied powers from 27 August 1916 until Central Power occupation led to the Treaty of Bucharest in May 1918, before reentering the war on 10 November 1918. It had the most significant oil fields in Europe, and Germany eagerly bought its petroleum, as well as food exports.
Generaloberst Arthur Freiherr Arz von Straußenburg was an Austro-Hungarian colonel general and last Chief of the General Staff of the Austro-Hungarian Army. At the outbreak of the First World War, he commanded the 15th Infantry Division. Soon, he was promoted to the head of the 6th Corps and the First Army. He participated on the Gorlice–Tarnów Offensive in 1915 and the countryside of Romania in 1916. In March 1917, he became Chief of the General Staff until his resignation on 3 November 1918.
The 9th Army was an army level command of the German Army in World War I. It was formed in September 1914 in Breslau to command troops on the southern sector of the Eastern Front. The army was dissolved on 30 July 1916, but reformed in Transylvania on 6 September 1916 for the Romanian Campaign. It was transferred to the Western Front on 19 June 1918 where it was finally dissolved on 18 September 1918.
The Supreme Commander of the Imperial and Royal Armed Forces was the ultimate authority of the Austro-Hungarian Armed Forces – which comprised the Army, Navy and Aviation Troops of Austria-Hungary.
The leaders of the Central Powers of World War I were the political or military figures who commanded or supported the Central Powers.
World War I began when Austria-Hungary invaded Serbia in July 1914, following the Assassination of Archduke Franz Ferdinand. Austria-Hungary was one of the Central Powers, along with the German Empire and the Ottoman Empire. Austro-Hungarian forces fought the Allies in Serbia, on the Eastern Front, in Italy, and in Romania. With heavy aid and support from its allies, the empire managed to occupy Serbia in 1915 and force Romania out of the war in 1917. On the other fronts, it suffered severe casualties, culminating in the collapse of the Italian front, which led the Austrians to accept the Armistice of Villa Giusti on 3 November 1918.
The 2nd Army, later designated East Army, was a field army-level command of Austro-Hungarian Army that was active during World War I. It was initially formed to take part in the Balkans Campaign before being transferred to the Eastern Front. In the final stages of the war, the army was evacuated from Ukraine before demobilizing in November 1918.
The 12th Army was a field army-level command of the Austro-Hungarian Army that existed only for one month during World War I, led by Archduke Karl Franz Joseph. It had been formed in response to the success of the Russian Empire's Brusilov Offensive, and was dissolved upon the formation of Army Group Archduke Karl.
The 3rd Army was a field army-level command within the ground forces of Austria-Hungary during World War I. It was primarily active on the Eastern Front against the Russian Empire and in the Balkans against Serbia and Montenegro. Later on, the 3rd Army took part in some fighting on the Italian Front before returning to the eastern theater by 1917 to repulse the Kerensky Offensive. Its remaining units were merged with the 7th Army in January 1918.
Alfred Georg Heinrich Maria Freiherr von Waldstätten was an Austro-Hungarian Army officer holding the rank of Generalmajor who served during World War I. He held senior positions on the Armeeoberkommando and possessed significant influence over the Chief of General Staff, Arthur Arz von Straußenburg, and Emperor Karl.
Karl Tersztyánszky von Nádas, officially Károly Tersztyánszky, also alternatively written Tersztyánszky de Nádas was an Austro-Hungarian general who served in World War I.
The Balkanstreitkräfte, also known as the Balkan Army, was the force raised by Austria-Hungary for its offensive action against Serbia in August 1914, at the start of the First World War.
Austria-Hungary 
Austro-Hungarian Army 