id to me, 'Buy it; it is very cheap. I
will sell it you for three dirhems; its owner is in need of money.' It
was a commentary of Al Farabi on the metaphysics of Aristotle. I bought
it, took it home and began to read it. Immediately all my difficulties
were cleared up, as I knew the "Metaphysics" by heart. I was delighted,
and the next day distributed alms to the poor in order to show my
gratitude to God."

About this time the Emir Nuh Ibn Mansur, prince of Khorassan, fell ill,
and having heard of Avicenna's talent, sent for him and was restored to
health under his treatment. As a reward, Avicenna was allowed to study
in the prince's library, which contained several chests of rare
manuscripts. Here he discovered treatises on the sciences of the
ancients, and other subjects, the essence of which he extracted. It
happened some time afterwards that this library was destroyed by fire,
and Avicenna remained the sole depository of the knowledge which it
contained. Some persons even said that it was he who had set fire to the
library because he alone was acquainted with its contents, and wished to
be their sole possessor.

At the age of eighteen he had completely mastered all the sciences which
he had studied. The death of his father and the fall of the Samanide
dynasty forced him to quit those literary treasures which he had learnt
to appreciate so well. At the age of twenty-two he left Bokhara and went
to Jorjan, the capital of Khwarezm where he frequented the Court of Shah
Ali ibn Mamoun. At this time the celebrated Sultan Mahmoud of Ghazni,
having heard that there were several learned men, and among them
Avicenna, at the Court of Mamoun, requested the latter to send them to
him. Several of them went, but Avicenna refused, probably because his
orthodoxy was suspected, and Sultan Mahmoud was a strict Sunni. Mahmoud
was much displeased at not seeing Avicenna appear at his court with the
rest, and sent descriptions and drawings of him in several directions in
order that he might be arrested. In the meantime, Avicenna finding the
allowance made to him at the Court of Mamoun insufficient, left Jorjan
and wandered through the towns of Khorassan. Finally he settled in a
little village near Balkh. There he composed the greater part of his
philosophical works, and among others the book on the "Eternal Principle
and the Return of the Soul." Some time afterwards he was called to
Hamadan to treat the Buwayhid Sultan Shams-ed Dawla, wh