The word manuscript derives from the Latin words for hand and writing. It refers to written information that has been manually created by one or more people.
We call a manuscript illuminated when decorations such as decorated initials, marginalia or miniature illustrations have been added. In the strictest use the term refers only to manuscripts with gold or silver decorations. Today however, the term is used for any decorated or illustrated manuscript from the Western traditions. This excludes manuscripts from the Eastern and Mesoamerican origin as these are generally said to be painted instead of illuminated. Text from the Islamic tradition can be referred to as either illuminated or painted.
Generally speaking manuscripts were commonly created between Late Antiquity and Renaissance. Before that time they used tabulae (wax covered boards) or stone to write on, afterwards they printed.
The earliest surviving illuminated manuscripts date back to the period AD 400 – 600. They are valuable not only because they are old and rather beautiful and more often than not the only surviving paintings of their period; manuscripts – illuminated or not – kept literacy and with it the literature of ancient Greece and Rome alive at a time when Europe had been overrun by barbaric hordes and the ruling class was no longer literate. There is a reason why we call it the dark middle ages. Yet, as the execution and use of manuscripts was in the beginning strictly limited to monastic scripts and a literate group of Christians, in Europe only texts survived that were useful to them. From the 14th century on also secular workshops produced illuminated manuscripts on commission, by the beginning of the 15th century these were producing most of the best work.
Thus said it is not surprising that most illuminated manuscripts are of religious nature. Only from the 13th century onwards we find also illuminated secular texts those number rose when secular workshops became more common. The introduction of printing rapidly led to the decline of illumination. By the early 16th century the creation of illuminated manuscripts was down to a few books for the very wealthy.
Classification of illuminated manuscripts:
Late Antique most likely Gospel Books
Romanesque Manuscripts whole Bibles, Psalters
Gothic Manuscripts Psalters, Books of Hours, secular