Boyan is the name of a bard who was mentioned in the Rus' epic The Lay of Igor's Campaign as being active at the court of Yaroslav the Wise. He is apostrophized as Volos's grandson in the opening lines of The Lay (probably a reference to Veles as the patron of musicians). Historians have been unable to determine whether Boyan was his proper name (as Nikolai Karamzin and Fyodor Buslayev postulated) or all skalds of Rus were called boyans (Alexander Vostokov). The Russian version of the button accordion is known as the bayan and was named after legendary Boyan upon its invention in 1907.