As typography developed the need for Unicial Script arose as the letters were always changed and improved, and it was necessary for a script to be written faster.
The solution was an Uncial script that saw the first lower case (small letters) appear. The writing surface also improved, as the type designers of the sixth century dropped rough papyrus, which was much smoother in favour of parchment. The rough writing tool, the calamus or reed pen, had been replaced by a much finer quill.
Some letters gained more and more pronounced descenders and ascenders, sticking up and down, creating an alphabet in a more refined four-line system.