Smolensk armies under Prince Mstislav II. The third group is the Galician-Volhynian army under Mstislav Mstislavich with his son-in-law Daniel of Galicia, leaving from northern Ukraine. The Mongol leaders Subutai and Jebe receive news that Jochi, who camps north of the Caspian Sea, will not be able to provide the expected reinforcements due to Jochi's reported illness or suspected refusal to obey his father Genghis Khan's orders. Subutai sends an embassy to the Russian princes, to offer peace and perhaps attempt to break the Russian alliance with the Polovtsians. But the Mongol ambassadors are executed – a task eagerly carried out by Köten Khan's followers, by the end of April. Late April – The Russian and Polovtsian armies march down the west bank of the Dnieper River. Within a few days of the march beginning, a second group of Mongol ambassadors appear in the Russian camp and again offer peace. When their offers are rebuffed, the ambassadors are allowed to leave unharmed. Meanwhile, Russian forces from Galicia arrive by boat or cart-loads of equipment and food, along the Black Sea coast and up the Dnieper River. Screened by Mongol forces on the east bank. May 15 – The Russian army gathers on the island of Khortytsia, later to become a famous Cossack base, at the mouth of the Dnieper River, next to modern-day Zaporizhzhia (Ukraine). The main Polovtsian forces led by Köten Khan, join the Russians here, which consist entirely of mounted archers. Compare to this, some 20,000–25,000 Mongols assemble and build a defensive encampment on the high ground, probably on the northern slopes of the Mohila Bel'mak hills, located near the Konka River. May 16 – Mstislav Mstislavich leads a small detachment of his own men, and some Polovtsians to the far bank of the Dnieper River – where they attack a part of the Mongol advance guard. The Mongols promptly fleeing into the steppes. Mstislavich pursues them and captures their commander named Gemyabek or Hamabek who seeks refuge behind a wooden fence surrounding a Polovtsian burial site. The captive's fate is sealed when the Polovtsians ask Mstislavich to hand him over – to execute. May 17 – Daniel of Galicia leads a reconnaissance in force east of the Dnieper River, using a bridge of boats. He defeats a Mongol detachment, who abandons their herds and local prisoners. Following these successful sorties, the entire Russian and Polovtsian armies start