Throughout history many nations have suffered a physical defeat, but that has never marked the end of a nation. But when a nation has become the victim of a psychological defeat, then that marks the end of a nation.
Ibn KhaldunAll the sciences came to exist in Arabic. The systematic works on them were written in Arabic writing.
Ibn KhaldunThe term of life of a dynasty does not normally exceed three generations. For in the first generation are still preserved the characteristic features of rough, uncivilized rural life, such as hard conditions of life, courage, ferocity, and partnership in authority. Therefore the strength of the 'Asabiya is maintained.
Ibn Khaldun