The Battle of Kagul or Cahul ( [Battle of the Kagul], [Battle of the Eagle Plain]) occurred on 1 August 1770 (21 July 1770 in Julian Calendar) during the Russo-Turkish War of 1768–1774. It was the decisive and most important land battle of the war and one of the largest battles of the 18th century. It was fought in Moldavia, near the village of Frumoasa (now Cahul, Moldova), nearly a month after the Russian victory at Larga.
While the army of the Ottomans and its Crimean Tatar vassals greatly outnumbered the Russian force opposite them, the Russian commander, Field Marshal Pyotr Rumyantsev, deftly arranged his far smaller army in solid infantry squares and surprisingly chose to go on the offensive against the allied forces. Assisting it is the superb coordination and firing rapidity of the Russian artillery, which effectively neutralized the Ottoman artillery and largely negated the numerical superiority of the Ottoman army. The result was a decisive Russian victory.
Background
The Russian empress Catherine II ordered the invasion of Moldavia and Wallachia, both of which states under Ottoman suzerainty, in September 1769 as a response to the Ottoman sultan Mustafa III's declaration of war against Russia the previous year. Leading the invasion endeavor was Field Marshal Pyotr Rumyantsev. Although the Ottoman forces, joined by Crimean Tatar forces from the east, had greater numerical superiority over the Russian forces, it was evident that they were buckling under the speed and shock of the Russian invasion, retreating after suffering losses from battles and sieges while their fortresses were falling one by one. The Ottoman sultan did not expect such a calamity to happen, but this shocked the Grand Vizier Ivazzade Halil Pasha even more that he had lost oversight of the overall situation in the theater and thus let the initiative pass to the enemy for the time being. To make matters worse, after the battle at Larga, the Ottomans and Crimean Tatars retreated in two different and distant directions which made assistance to each other for the next battle nearly impossible: the Tatars retreated to the direction of Izmail and Kiliya, while the Ottomans retreated towards the village of Frumoasa, now called Cahul, near the Kagul River.
Despite losing the engagement at Larga and the fact that nearly all of Wallachia and Bessarabia was in Russian hands, Ivazzade Halil Pasha believed that retaking the initiative from the Russians was still possible. It only helped convince him such when the Crimean khan Qaplan II Giray sent him Russian prisoners whom the Ottomans thoroughly interrogated. The Grand Vizier found out that the smaller Russian army was nearing the end of its campaign capability, with its food supplies and ammunition stocks nearing depletion. It was then he decided that he had to order a grand counterattack against the Russian force forcing its way across the riverine region of southeastern Moldavia. At that end, the Grand Vizier rushed back to the Ottoman capital Constantinople to discuss matters with the Sultan and other Ottoman commanders involved, thus starting an emergency council of war which lasted several days. After some time in preparation and deliberation, the Grand Vizier returned to the theater and managed to reinforce his army, which had been gravely depleted after several crushing battlefield defeats. He gathered a sizeable army consisting of 150,000 men-at-arms gathered from all parts of the empire at his disposal by mid-July, many of whom were ferried by 300 ships from across the Danube River.
Prelude
After assigning the subordinates to their respective positions, the Ottoman Grand Vizier Ivazzade Halil Pasha promised to the army that there would be no defeat by the Russians this time, and likewise the army and their commanders responded that there would be no backing down on the effort at winning the battle no matter the cost. With the reinforced and rebuilt Crimean Tatar army of 80,000 cavalry only from his position, he was confident of total victory against the smaller Russian army marching towards his army nearby.