The literary expression of Persian sufism

It is in itself impossible to separate Persian mysticism from Islamic mysticism in general. When talking about the literary expression of Persian Sufism, the author restricts himself to works written in New Persian language, i.e. a limitation based on literary and not religious criteria. This is easily comprehensible considering the fact that one and the same Sufi shaykh or poet often wrote both in Persian and Arabic—or in some other of the languages of the Islamic cultural community, as e.g. Turkish or Urdu. With this in mind the author sketches the origin and development of four literary forms within the boundaries of classical Persian literature (c. 900-1600 A.D.)