The earliest known example of an historiated initial—an enlarged letter at the beginning of a paragraph or other section of text which contains a picture—is in the St Petersburg Bede, an Insular manuscript, which was written about 750 CE. Only four 8th century manuscripts of Bede survive. The St. Petersburg Bede and the manuscript known as the "Moore Bede" are the earliest witnesses to Bede's text.
The Saint Petersburg Bede
"Traditionally, the Saint Petersburg Bede is attributed on palaeographic grounds to Bede’s monastery at Wearmouth-Jarrow. It is also traditionally dated to 731/732 × 746 on the basis of the so-called Memoranda, a series of retrospective dates found in the margins of Bede’s recapitulo in Book V Chapter 24. The validity of these Memoranda (and similar notes in the Moore Bede) as evidence for the precise year in which the manuscript was copied has been vigorously challenged. While it may not be possible to assign the manuscript to a specific year, it seems unlikely that it was copied much after the middle of the eighth century." (Wikipedia article on the Saint Petersburg Bede, accessed 11-22-2008)
The Saint Petersburg Bede (Saint Petersburg, National Library of Russia, lat. Q. v. I. 18), formerly known as the Leningrad Bede, is one of the two earliest surviving illuminated manuscripts of Bede's Historia ecclesiastica gentis Anglorum (Ecclesiastical History of the English People). It was taken to the Russian National Library at the time of the French Revolution.
The Moore Bede
"The Moore Bede is traditionally dated to 734 × 737 on the basis of the so-called Moore Memoranda, a series of chronological notes preserved on f. 128v. Although the validity of these (and similar notes in The Leningrad [St. Petersburg] Bede) as evidence for the manuscript’s date has been challenged vigorously, the manuscript can be dated securely to the eighth century on palaeographic and codicological grounds.
"The manuscript is now thought "likely to be English in origin" (Ker 1990). Bischoff has shown that the manuscript was at the Palace School at Aachen around CE 800 (Bischoff 1966–1968, 56). Parkes suggests that it may have been sent to there from York at the request of Alcuin (Parkes 1982, 27, n. 35)" (Wikipedia article on the Moore Bede, accessed 11-22-2008).
The Earliest Surviving Copies of Caedmon's Hymn
♦ The Moore Bede and the St. Petersburg Bede also contain the earliest known copies of Caedmon's Hymn, the only surviving work of the earliest English poet whose name is known.
"The poem is one of the earliest attested examples of Old English and is, with the runic Ruthwell Cross and Franks Casket inscriptions, one of three candidates for the earliest attested example of Old English poetry. It is also one of the earliest recorded examples of sustained poetry in a Germanic language" (Wikipedia article on Caedmon, accessed 01-12-2010).