In 1744 Swedenborg traveled the Netherlands to gather material for a scientific treatise on the anatomy and behavior of animals. En route, he began having strange and disturbing dreams. It was Swedenborg's custom to keep a diary while he traveled, and so he recorded his dreams in its pages. These visions began the process of Swedenborg's spiritual awakening, which culminated in visions of angels, demons, heaven and hell. Swedenborg would largely abandon scientific pursuits and instead devote himself to recording the mystical visions that would dominate his legacy. The whereabouts of this journal were unknown for decades after Swedenborg's death, but it was eventually discovered in the Royal Library in the 1850s and subsequently published.