When looking back at the history of diary, many records start with the advent of paper production in China during 100 BC. Prior mediums of writing, papyrus and parchment were difficult to write on due to its delicate nature and cost of production.
Even after the invention of paper in during the dawn of the AD era, it took another thousand years before people were using paper all over Eurasia. Indians started making paper during the 400s AD, and by the 600s, paper had reached Korea and Japan as well. Meanwhile, Europeans were still using parchment or buying their paper from Egypt at extremely high prices. Soon they too realized the benefits and joys of paper and thus the creation of paper mills began to dawn in Italy 1250 AD.
Somewhere during the proliferation of paper in Asia and Europe, diaries started to be documented. Some notable milestones of diaries in history:
Many diaries were written as travel journals such as that made by the Chinese philosopher and writer 李翱 (Li Ao, 772–841). Widely recognized as the earliest paper diary in the world, this was documentation of the journey made by Li and his pregnant wife from Luoyang to Guangzhou over nine months in 809 AD.
The earliest surviving diary actually written in English is that of an anonymous diplomat known only as 'One of the Suite of Thomas Beckington', which records his embassy to France to arrange the marriage of King Henry VI and a daughter of the count of Armagnac, from June 1442 to the following January.
However, perhaps the earliest recognized diary in the world is that of Roman Emperor Marcus Aurelius during 180 AD. Now titled Meditations, his thoughts were transcribed in a series of untitled chapters, as it was not meant for public publication. A fascinating history by ‘boopoo3894’ on Reddit is follows,
- The Meditations were preserved, through unknown means, at least from their writing in 180 AD to 900 AD. So far, absolutely nothing is known about who preserved them other than it probably wasn't a rare manuscript to find at all, at least in the Eastern Roman (Byzantine) Empire
- Around 900 AD, a Byzantine scholar named Arethas of Caesarea found a manuscript of the Meditations, fell in love with it, copied it, and began to prolifically mention it left and right in his letters and works, although he implied that the Meditations were already known to Byzantine scholarship even before him. All surviving Byzantine mentions of the work, however, come after Arethas
- Around 1300 AD, a lot of fragments of the Meditations began to appear in the West, and the oldest manuscript we currently possess of it was written down (currently in the Vatican Library). It is quoted for the first time in the West in 1517
- In 1558 or 1559, the German scholar Wilhelm Xylander printed the first printed edition of the Meditations, beginning modern scholarship and popular knowledge of the work