Massage
One of the greatest Persian medics was Avicenna, also known as Ibn Sina, who lived from 980AD to 1037AD. His works included a comprehensive collection and systematisation of the fragmentary and unorganised Greco-Roman medical literature that had been translated Arabic by that time, augmented by notes from his own experiences. One of his books, "Al-Qānūn fī aṭ-Ṭibb" (The Canon of Medicine) has been called the most famous single book in the history of medicine in both East and West. Avicenna excelled in the logical assessment of conditions and comparison of symptoms and took special note of analgesics and their proper use as well as other methods of relieving pain, including massage.
Islamic philosophy
The idea of "essence precedes existence" is a concept which dates back to Ibn Sina (Avicenna) and his school of Avicennism as well as Shahab al-Din Suhrawardi and his Illuminationist philosophy. The opposite idea of "Existence precedes essence" was thus developed in the works of Averroes and Mulla Sadra as a reaction to this idea and is a key foundational concept of existentialism.