Several elements of courtly love were developed in Arabic literature, namely the notions of "love for love's sake" and "exaltation of the beloved lady" which have been traced back to Arabic literature of the 9th and 10th centuries. The notion of the "ennobling power" of love was developed in the early 11th century by the Persian psychologist and philosopher, Ibn Sina (known as "Avicenna" in Europe), in his Arabic treatise "Risala fi'l-Ishq" ("Treatise on Love"). The final element of courtly love, the concept of "love as desire never to be fulfilled", was also at times implicit in Arabic poetry.