Wilhelm Storost, artistic name Vilius Storostas-Vydūnas, mostly known as Vydūnas, was a Prussian-Lithuanian teacher, poet, humanist, philosopher and Lithuanian writer, a leader of the Prussian Lithuanian national movement in Lithuania Minor, and one of leaders of the theosophical movement in East Prussia.

The Prussian Lithuanians, or Lietuvininkai, are Lithuanians, originally Lithuanian language speakers, who formerly inhabited a territory in northeastern East Prussia called Prussian Lithuania, or Lithuania Minor, instead of the Grand Duchy of Lithuania and, later, the Republic of Lithuania. Prussian Lithuanians contributed greatly to the development of written Lithuanian, which for a long time was considerably more widespread and in more literary use in Lithuania Minor than in Lithuania proper.