What did Ibn Khaldun say about the origin of Sufism?

The historian Ibn Khaldun counts the science of Tasawwuf among the sciences of the religious law that originated in Islam. He writes that the special name of Sufis was given later, at a time when worldly aspirations increased and people inclined more towards worldly affairs.

Some people may say that the term Tasawwuf did not exist in the times of the Beloved Prophet ﷺ. The term Tasawwuf, like many other Islamic disciplines, came into origin after the first generation of Muslims, and Ibn Khaldun writes in his book Muqaddimah:

"The science of Tasawwuf belongs to the sciences of the religious law that originated in Islam. Sufism is based on (the assumption that) the method of those people (who later on came to be called Sufis) had always been considered by the important early Muslims, the men around the Last Prophet Muhammad ﷺ and the men of the second generation, as well as those who came after them, as the path of truth and right guidance.

"The (Sufi) approach is based upon constant application to Divine worship, complete devotion to Allah, aversion to the false splendour of the world, abstinence from the pleasure, property and position to which the great mass aspires, and retirement from the world into solitude for Divine worship. These things were general among the men around Allah's Last Apostle Muhammad ﷺ and the early Muslims. Then, worldly aspirations increased in the second (eighth) century and after and people inclined more towards worldly affairs. At that time, the special name of Sufis (Sufiyah and Mutasawwifah) was given to those who aspired to Divine worship." [Ibn Khaldun, Muqaddimah]