The Battle on Pyana River (Russian: Сражение на реке Пьяне) took place on August 2, 1377 on the Pyana River between the Golden Horde under Arab Shah (Arapsha) and an alliance of Russian principalities led by Prince Ivan Dmitriyevich, made up of the Pereyaslavl, Yaroslavl, Yuryev, Nizhny Novgorod, and Murom principalities.

[1] The Russian army, being drunken, was almost entirely routed by small forces of Arapsha, while Ivan Dmitriyevich had drowned together with druzhina and staff.

[2] The corresponding events are further recorded in the medieval Russian Chronicle On The Slaughter at Pyana River.

Young knyaz Ivan Dmitriyevich, who assumed the joint command, moved the troops to River Pyana.

Because of hot weather, the awaiting Russian warriors began wandering around and consuming alcoholic beverages like mead and beer, which the troops of Suzdal prince drank while waiting in the local villages for the battle to begin.