Journaling is not a modern phenomenon; there are recordings traced back to 55AD China. During the Renaissance period, the Western world began journaling regularly and the diary, began to have some literary value as the importance of the individual began to come to the fore. Ladies of the court in tenth century Japan used pillow books to record their dreams and thoughts with images and poetry. Throughout history, travel logs were also used as journals in both the Eastern and Western worlds. They were used to record details of places, people, navigational insights, botanical and other information. Since then it has often been used by the historian, not only as a supply of factual information, but as a picture of the daily life and personality of its writer.
Read more at A Brief History of the Journal.