Sufism
At first, Sufism only meant making Islam more personal and internal. Some say it first came from constantly reciting the Qur'an, meditating, and through experience. Others believe that Sufism is trying to live as the Islamic prophet Muhammad did, to be closer to God. This is how the Prophet taught his disciples. Additionally, the Muslim conquests had brought large numbers of Christian monks and hermits, especially in Syria and Egypt, under Muslim rule. They believed in a deeply spiritual and mystical (even 'Platonic')  way of life and many of their ways became part of early Sufism.