Deriving from Neo-Platonism and Henosis, mysticism is popularly known as union with God or the Absolute. In the 13th century the term unio mystica came to be used to refer to the "spiritual marriage," the ecstasy, or rapture, that was experienced when prayer was used "to contemplate both God's omnipresence in the world and God in his essence." In the 19th century, under the influence of.