The opposite situation is that of imperfect manuscripts which dominate reception for hundreds of years. One of these interesting cases, the Orations of Isocrates, has just appeared online at the Vatican Library portal (full list below). Vat.gr.65.pt.1 is an 11th-century manuscript of the speeches of the ancient Greek rhetorician Isocrates, exactly datable to 1063.
I learn from a review by Pasquale Pinto that its text of the Antidosis, a long oration on morality, Athenian customs and Isocrates' own life looking back aged 82, is in fact incomplete, but was relied on for the early printed editions:
A complete text was rediscovered only at the beginning of the 19th century in four Mss.: the Vat. Urb. Gr. 111 (Γ) with its two close descendants (Vat. Gr. 936 [Δ] and Ambros. O 144 sup. [Ε]) and the Laur. plut. 87.14 (Θ). The remaining extant Mss. (the Vat. Gr. 65 [Λ] and 12 other Mss. ultimately deriving from it) all display a vast lacuna between § 72 and § 310, which affected nearly 3/4 of the text. The Ant. was therefore known in this shorter form for centuries, from when it was first printed in Milan in 1493, in the editio princeps of Is.’ works from a mutilated Ms. Only in 1811–1812, did a Greek scholar living in Italy, Andreas Mustoxydis, find Θ and Ε and publish the first complete edition of the speech (Milan 1812).Pinto notes that this was "one of the last great discoveries of ancient texts before the age of papyri".
For a list of the main Isocrates manuscripts, see Roger Pearse. For a thesis in Italian by Stefano Tempesta closely examining the Panegyricus in the same manuscript, see Academia.edu.
Here is my list of novelties from the past few days. These bring the full harvest to 13,331 codices.
- Vat.gr.65.pt.1 (above), an 11th-century manuscript of the speeches of the ancient Greek rhetorician Isocrates
- Vat.iber.1, the four Gospels in Old Georgian (not Iberian as the shelfmark might suggest)
- Vat.lat.1199, Life of Anthony by Athanasius, Evagrius latin translation
- Vat.lat.1204, John the Deacon on Gregory the Great
- Vat.lat.1291, 14th and 15th century theological, including on Cathars
- Vat.lat.1331, translation to Latin of documents of Council of Nicea by famed 9th-century papal staff scholar Anastasius Bibliothecarius (HT to @LatinAristotle )
- Vat.lat.1600, Ovid
- Vat.lat.2063 Plato: dialogues Timaeus and Phaedo, in translations by the Chalcidius of antiquity and 12th-century Henricus Aristippus. This is a manuscript owned by the Florentine Renaissance humanist Coluccio Salutati (HT to @LatinAristotle).
- Vat.lat.9490, a codex purpureus prayer-book by Bartolomeo Sanvito, a Renaissance scribe. (HTto @gumdormr who points out it is a book of hours made about 1469 for one Diomede Carafa, according to C. de la Mere, pp 210-211).
- Vat.lat.15416, Pietro Combi, collection of stone inscriptions
By the way, read as well Roger Pearse's appeal today for users of the Vatican Library site to make donations, Let's not shout at the Vatican Library for Digitising Microfilms. The library is rich in capital but poor in income, and I can entirely support what Roger has to say.