The project focuses on the journey of the Russian Grand Prince Alexander Nevsky to the Golden Horde in the 13th century. According to certain historical traditions—most notably popularized by the historian Lev Gumilev—Nevsky established a deep strategic alliance and performed a blood brotherhood ritual (pobratimstvo) with Sartak, the son of Batu Khan.
Sartak was an adherent of Nestorian Christianity, which provided a unique common ground, fostering mutual respect, shared prayers, and a peaceful political bond between the Russian principality and the Mongol steppe.