The first standard latin script which consisted of both majuscule and minuscule letters (lowercase and uppercase, or small and capital letters) in one word is Carolingian minuscule. It is a fact. But what is unknown to me (and as far as I know is unknown to all scholars) is the first purpose or first use of capital letters. Does anybody know any clear evidence that reveals the first application of capital letters. Was it used, for the first time, to distinguish the word and the names of God? Is it a biblical and christian effect? Or was it used to apply clarity for dividing sentences and paragraphs? Or the first use of capital was to highlight all proper names? Which of these applications was the first one? And I know that the capital letters came first, and at the beginning there was only CAPITAL. So from Carolingian minuscule, they used firstly capital for which purpose and use?
The Harley Gospel in the British Library (shelf number Harley MS 1775) "4th quarter of the 6th century," has distinct Capitals for the first letter of new Chapters (Capita) and at the end of Matthew two lines of Capitals in the EXPLICIT.
On the linked page there are three Capitals larger and with emphasised serifs.
On other pages, capital U becomes V; and the capital P has no descender.
Yet I cannot find special treatment for Names of any sort.
Another book which pre-dates Charlemagne is the Cuthbert Gospel (Stonyhurst Gospel) ?730, which is also in the BL. Again, there is a separate design for Upper Case, which is not used for every sentence, but marks paragraphs and chapters.