According to Francis X. Gumerlock, in Carolingian Commentaries on the Apocalypse by Theodulf and Smaragus, p. 2 (introduction):
In the first decade of the ninth century, Theodulf created scholarly editions of the Bible with variant readings referring back to the Hebrew. Concerning those editions, scholars have remarked how similar his approach was to "the modern method of constructing a critical text."[EN9] In addition, he supervised the production of many Bibles, six of which have survived.
Endnote found at page 21:
EN9 E. K. Rand cited in Freeman, "Theodulph of Orléans and the Libri Carolini," 693. Greeley ("Social Commentary," 154) said that there was "no other instance of Biblical scholarship in the Middle Ages or even during the early Renaissance that so closely resembles the modern method of creating a critical text."
