Textual critics count four uncial codices as their most important early witnesses to the Greek New Testament: Sinaiticus, Vaticanus, Alexandrinus, and Codex Ephraemi Rescriptus, all four now catalogued in this atlas. Of the four, Ephraemi has the strangest afterlife. Copied in the fifth century, it was scraped clean in the twelfth, its biblical Greek washed and rubbed away, and written over with a Greek translation of sermons and hymns by Ephrem the Syrian, the fourth century Syriac deacon whose writing remained popular enough eight centuries later that a scribe judged it worth more parchment space than an aging Bible.
The recycling was not unusual for its period, parchment was costly and reuse was routine, but it left behind exactly the kind of layered object this atlas exists to catalogue: a fifth century Bible manuscript surviving only as the erased foundation beneath a twelfth century Christian text about a different Christian writer entirely. What survives of the lower, older text, 208 leaves in total, still touches nearly every book of the New Testament and a handful from the Old, making Ephraemi one of the most substantial early biblical manuscripts to survive at all, however indirectly its survival came about.