The Codex Alexandrinus (London, British Library, MS Royal 1. D. V-VIII; Gregory-Aland no. A or 02, Soden δ 4) is a 5th century manuscript of the Greek Bible, containing the majority of the Septuagint and the New Testament. It received the name Alexandrinus from its having been brought by the Eastern Orthodox Patriarch Cyril Lukar from Alexandria to Constantinople. Wettstein designated it in 1751 by letter A, and it was the first manuscript to receive thus a large letter as its designation.
Along with the Codex Sinaiticus and the Codex Vaticanus, it is one of the earliest and most complete manuscripts of the Bible. It derives its name from Alexandria where it resided for a number of years before being given to the British people in the 17th century. Until the later purchase of the Codex Sinaiticus, it was the best manuscript of the Greek Bible deposited in Britain. Today, it rests along with Codex Sinaiticus in one of the prominent showcases in the Department of Manuscripts of the British Library.
The book is in quarto, and now consists of 773 vellum folios (630 in the Old Testament and 143 in the New Testament), bound in four volumes (279 + 238 + 118 + 144). Three volumes contain the Septuagint, Greek version of the Old Testament, with the complete loss of only ten leaves. The fourth volume contains the New Testament with 31 leaves lost. The codex contains almost a complete copy of the LXX, including the deuterocanonical books 3 and 4 Maccabees, Psalm 151 and the 14 Odes. The "Epistle to Marcellinus" attributed to Saint Athanasius and the Eusebian summary of the Psalms are inserted before the Book of Psalms. It also contains all of the books of the New Testament, in addition to 1 Clement (lacking 57:7-63) and the homily known as 2 Clement (up to 12:5a).
There is an appendix marked in the index, which lists the Psalms of Solomon and probably contained more apocryphal/pseudepigraphical books, but it has been torn off and the pages containing these books have also been lost.
Due to damage and lost folios, various passages are missing or have defects: