In the Dove Book and other medieval Russian books, Buyan (Russian: Буя́н, sometimes transliterated as Bujan[1]) is described as a mysterious island in the ocean with the ability to appear and disappear using tides. Three brothers—Northern, Western, and Eastern Winds—live there, and also the Zoryas, solar goddesses who are servants or daughters of the solar god Dazhbog.[2]

It figures prominently in many famous myths; Koschei the Deathless keeps his soul or immortality hidden there, secreted inside a needle placed inside an egg in the mystical oak-tree; other legends call the island the source of all weather, created there and sent forth into the world by the god Perun.

Source: Buyan – Wikipedia