He was nominated tutor of Ahmad ibn al-Mu'tasim...

He was nominated tutor of Ahmad ibn al-Mu'tasim, to whom he dedicated some of his important writings. Ibn Nabatah says: “Al-Kindi and his writings embellished the empire of al-Mu`tasim.”[^3] He flourished also under the reign of al-Mutawakkil (r. 232-247/847-861). A story related by Ibn Abi Usaibi'ah indicates the great fame of al-Kindi at that time, his advanced knowledge, and his famous private library.

This is the full account: “Muham­mad and Ahmad, the sons of Musa ibn Shakir, who lived during the reign of al-Mutawakkil, were conspiring against everyone who was advanced in know­ledge. They sent a certain Sanad ibn 'Ali to Baghdad so that he might get al-Kindi away from al-Mutawakkil. Their conspiracies succeeded to the point that al-Mutawakkil ordered al-Kindi to be beaten.

His whole library was confiscated and put in a separate place, labelled as the 'Kindian Library.”[^4]' Al-Kindi's notoriety for avarice was equal to his fame for knowledge. This bad repute was due to al-Jahiz's caricature of him in his Kitab al-Bukhala' . However, al-Kindi lived a luxurious life in a house, in the garden of which he bred many curious animals. It seems that he lived aloof from society, even from his neighbours.

An interesting story related by al-Qifti shows that al­-Kindi lived in the neighborhood of a wealthy merchant, who never knew that al-Kindi was an excellent physician. Once the merchant's son was attacked by sudden paralysis and no physician in Baghdad was able to cure him. Some­one told the merchant that he lived in the neighborhood of the most brilliant philosopher, who was very clever in curing that particular illness. Al-Kindi cured the paralyzed boy by music.

Works Most of his numerous works (numbering about 270) are lost. Ibn al-Nadim and following him al-Qifti classified his writings, most of which are short treatises, into seventeen groups: (1) philosophical, (2) logical, (3) arithmetical, (4) globular, (5) musical, (6) astronomical, (7) geometrical, (8) spherical, (9), medical, (10) astrological, (11) dialectical, (12) psychological, (13) political, (14) causal (meteorological), (15) dimensional, (16) on first things, (17) on the species of some metals, chemicals, etc.

This account shows to what extent al-Kindi's knowledge was encyclopedic. Some of his scientific works were translated by Gerard of Cremona into Latin and influenced very much the thought of medieval Europe. Cardano considered him to be one of the twelve greatest minds.