Here's the opening. It will be introductory like this for some time to help educate the reader on the going-ons of the area and period, as most don't understand the extent and severity of the Horde's invasion.
Winter of 1237- West of the Russian Ural Mountains
With a voracious appetite, the Horde, as it became known, had already pillaged and burned the countryside and holdings of the Bulgar people, who lived east of the Volga river, and taken the city of Sarai near its out-pour into the Caspian Sea. That tributary and its several bridges and roads leading West were a sign to the vanguards of Batu Khan and Subedai Bahadur that yet more rich lands lay beyond, filled with treasure for their Khans, pasture for their horses, and women for their men. They led their troops in the ways the horde had perfected. Miles apart large contingents were kept in constant contact through special arrows that whistled in the wind or by waving flags. There were couriers who bound their bodies in tightly wound silks and leathers, who rode their horses without stopping up and down the Mongol roads all the way back to the capitol of Karakorum. In this way the might of 120,000 Mongolian horseman, conscripts and soldiers pressed across the frozen Volga river. Ahead of them their many spies and scouts were fanned, into the Russian people's lands of Moscow and Vladimir, in the holdings of every Russian city. Their detailed reports told Batu and Subedai something they already knew; their approach across the vast forests of the Volga's West bank had gone unnoticed, and there was much land to be claimed. With an empire already stretched from Korea to the Caspian Sea, the Mongol army that was to become the Golden Horde entered the lands of Riazan and the Suzdal Russians, starting the conquest of Eastern Europe in earnest.