His collection was noteworthy: the detailed inventory lists (prepared by his monks after his departure, and preserved in an appendix to a copy of the Martyrology of Usuard) only three complete volumes of theology, and focused heavily on classical literature and commentary thereon. The accepted biography, however, was questioned by a number of scholars since the late 20th century, with Daniel Verhelst, the most recent editor of the letter on Antichrist, being the first to doubt what is called the "long chronology", followed by Monique Goullet, editor of Adso's hagiographies. Its sourcing was already questionable, with one of the corroborating pieces of evidence a charter that was in fact used by the author of Adso's biographical sketch. This accepted account has Adso lead an extremely long life, going to Jerusalem sometime between age 72 and 82. But if his birth is placed close to 920, to have him on his pilgrimage as young as possible, he could hardly have been a teacher of renown in the 930s at Toul and either way it begs the question of why it took a scholar of such renown over 30 years to gain an abbacy. Another complicating factor is the "Life of Clotilde", a hagiography of Clotilde possibly written for Gerberga of Saxony, the recipient of the letter on Antichrist, whose author is argued by a number of scholar to be identical with the author of the letter. Goullet proposes a somewhat shortened biography, with Adso born in the 930s--which would mean that he would have written the letter possibly as a teenager. Simon Maclean proposes a radically different solution: in a nutshell, he suggests two Adsos ("Adso" being a very common name at the time)--the one, of Montier-en-Der, the author of the hagiographies; the other, Adso the abbot of St-Basle Abbey at Verzy (c. 970 – c. 991), whose epitaph was written by Adso of Montier-en-Der. Verzy is near Rheims, one of the most important locations in the sphere of influence of Gerberga, and a center of the monastic reform which she was interested in. This Adso, then, could be the author of the letter and of the "Life of Clotilde". The largest remaining part of Adso's literary output consists of hagiographies; he wrote the lives of five saints: Mansuetus, Frobert of Troyes, Waldebert, Basolus and Bercharius, and a short "libellus" on the translation of and miracles associated with Basolus.