Battle of Samara Bend

The Bulgars were nomadic tribes originally from the Pontic–Caspian steppe just north of the Black Sea.[2] In the mid-7th century, the group split; some migrated westward to Central Europe, forming the First Bulgarian Empire in the Balkans, while others migrated northeastward towards the confluence of the Volga and Kama rivers near modern-day Kazan, founding Volga Bulgaria.[3] The Volga Bulgars converted to Islam after it was declared the official state religion in 922,[2] establishing significant trade between the Islamic world and Europe.

Despite peaceful relations with Kievan Rus' during the 10th and 11th centuries, the principality of Vladimir-Suzdal began expanding its territory in the middle Volga region during the 12th century, and subsequent disputes over trade in the region resulted in hostilities with the Volga Bulgars. Various Bulgar towns and villages were conquered by the Kievan Rus', referred to as Brjahimov in old Bulgar.

The conquest led the Bulgars to establish a new capital at Bilar (also known as Biljarsk or Biler),[4] and the weakening of the Volga-Bulgar state.

On 12 January 1221, Shah Muhammad II of Khwarezm died while retreating from the Mongols on the island of Abeskum[5] during Genghis Khan's destruction of the Khwarezmid Empire. Upon hearing the news of the Shah's death, Genghis Khan summoned his general, Subutai, to Samarkand. Subutai offered him advice on how best to defeat the new Shah, Jalal ad-Din Mingburnu. He requested not to be part of the final campaign, and instead proposed to reconnoiter the west bank of the Caspian Sea and the steppes beyond. Genghis Khan accepted this plan and assigned two tumens (totaling 20,000 soldiers) to Subutai and another to Jebe, another one of the Khan's generals, under the condition that the campaign did not take more than two years and that on their return they find and join with the Khan's son Jochi in the east to engage the Volga Bulgars. Subutai rejoined Jebe at their camp near the Caspian at the delta of the Kura river. The "reconnaissance in force" began at the end of February 1221. The Mongols then invaded Georgia and decimated George IV of Georgia's much larger forces on the plain of Khuman, sacking Mariah and Hamadan.

The Mongol forces crossed the Caucasus with significant difficulty during the winter. After crossing, they met an army of some 50,000 allied Circassians, Alans, and Lezgins, who were joined by Cumans;[6] the Cuman forces were further bolstered by their Volga Bulgar, Khazar, and Avar allies under the command of their khagan Kotian's brother, Yuri, and son, Daniel. After an inconclusive first battle, the Mongols bribed the Cumans to abandon their allies by promising them half their spoils from Georgia.[6] The Cumans broke camp during the night, leaving their allies to the Mongol horde, who sacked the camp and impressed the survivors they considered useful into their army.

The Mongols later overtook and massacred the fleeing Cumans, among whom were Yuri and Daniel. In addition to this victory, the Mongols also recovered their treasure used for the bribe. Upon hearing the news of this defeat, many Cumans fled west to the borders of Hungary and the Byzantine Empire's trading station on the Sea of Azov.

The Mongols sacked Astrakhan, after which Subutai and Jebe split their forces. Subutai marched south to the Sea of Azov to ensure that the Cumans could not threaten them from the rear, while Jebe marched to the Don river to await him. Subutai's force attacked and razed settlements along the shore, massacring any Cumans they encountered. It was during these advances that the Mongols encountered Venetian merchants for the first time. Subutai made a pact with them to destroy their Genoese rivals' trading posts in exchange for information and military intelligence on the west.

In accordance with the pact, Subutai destroyed the Genoese trading station of Soldaia (Sudak) in Crimea, after which he rejoined Jebe. The Mongol forces were then composed of perhaps 25,000 men, who marched unopposed to the Dniester river. In the meantime, Jebe had allied with the chief of the Brodnici, Polskinia, and 5,000 Brodnici troops joined his forces on the Don.

In the autumn and winter of 1222, the Mongol army marched up and down the Dniester, frequently resorting to scare tactics to discourage attacks. Scouting parties were sent as far west as possible to gather military intelligence on southern Kievan Rus' and the states along the borders of the Carpathian Mountains. Their objective completed, the Mongols began their march home.

The Cuman leader, Kotian, had fled north with the remnants of the Cumans and pleaded for an alliance with the Ruthenian (Rus') princes against the Mongols at a conference. The Ruthenian princes of Galicia (Mstislav the Daring), Kursk, Kiev, and Chernihiv agreed to join Kotian to stop the Mongols. Duke Yuri of Suzdal also promised to send an army under the command of his nephew, the Prince of Rostov. The nominal strength of this allied force was 80,000 men.

The Mongols learned that military action was being planned against them by their spies and scouts; the allied Rus' and Cuman forces approached the Mongol position from several directions. The Mongols were still under the Khan's orders to suppress the Volga Bulgars, but this could not be safely done with enemies in their rear, and the elimination of the incoming Ruthenian threats was a military necessity. They crossed the Dnieper where the expected rendezvous with Jochi did not take place; Jochi was supposedly ill and delayed in the east. After Mongol ambassadors to the Princes of Chernihiv and Kiev were killed, they declared war.

Subutai and Jebe left one thousand men under the command of Hamabek on the east bank of the Dnieper to delay the Ruthenian crossing—this rearguard was able to inflict heavy casualties but was eventually overwhelmed and destroyed, and Hamabek was captured and executed. In May 1223, the Mongols retreated over the steppes north of the Sea of Azov, land that they knew well. Although their mobility allowed them to easily outpace the Rus' forces, they instead decided to confront them. On 31 May 1223, they stopped along the western bank of the river Kalka (Kalmyus). In the ensuing Battle of the Kalka River, Mongol forces of perhaps 23,000 exterminated the combined Cuman-Ruthenian army, which may have numbered 80,000 men,[6] only 25–30% of which were experienced warriors.[7] The Mongol tactics and weaponry, with which the Ruthenians had no prior experience, were superior to the rather unorganized assault by the allied armies. The Mongols pursued the remnants of the allied forces to the Dnieper, where the Prince of Kiev had retreated with his army mostly intact, not having been part of the reckless charges at Kalka; however, they were overtaken by the Mongols and eventually massacred in their fortified camp. The Prince of Rostov stopped and returned with his army to Suzdal upon the news of the defeat at Kalka to prepare for an attack, but it never came. The Mongols had resumed their march east.[8][9][10]

The Mongol campaign had killed as many as 200,000 soldiers from various nations and, up until this point, had never lost a major battle. At this point in history, the Mongol army was the finest in the world—it was professional and extremely well-trained and equipped. A Mongol rose through the ranks based on his merit rather than his position in Mongol society, and generals such as Jebe, Subutai, and the Great Khan had developed revolutionary tactics all controlled with iron discipline. Its mobility was unmatched by any other military force. Using the Mongolian horse (steppe pony) allowed the survival of their steeds in areas where other horses would have starved or otherwise died from conditions. Mongol commanders also realized the quality of their army and were not impressed by the mere size of the opposing forces of their enemies. They could stand and hold, and their tactics would often cause an enemy to break and retreat in a panic that inevitably led to a rout by Mongol mounted archers and lancers. They often employed siege engines and engineers from China and Persia in their ranks to enable them to take fortified cities, although this would not have been practical in the fast campaign of Jebe and Subutai.[11] This was the army now marching to face the Bulgars on the Volga.