Al-Farabi (born 872 - d. 950) was nicknamed "The Second Teacher" by Aristotle. He was the first scholar to classify science and philosophy in the Islamic world. In his famous work "Al-Madina al-Fadila" (perfect city) he describes a model society and leaders with high morals and wisdom. He stressed that the ultimate goal of philosophy and religion is to achieve true happiness (Sa'adah) of mankind, both in this world and in the world to come.