Codex Alexandrinus is one of the four Great uncial codices and among the earliest and most complete manuscripts of the Bible. It is the oldest manuscript to use larger letters to indicate new sections, and it was the first manuscript of great importance and antiquity to be extensively used by textual critics.

It contains the Book of Revelation with a commentary by Andreas of Caesarea written in cursive letters. The manuscript's uncial letters uniquely lean to the right.