Ælfric himself states at the beginning of the work that it contains material of ðære bec þe Beda se snotera lareow gesette, but he does not specify which book. Early in his career, in about 703, Bede published two straightforward works of instruction, De temporibus and De natura rerum, on chronology and natural science respectively. Some years later, in about 725, he published a comprehen-sive and highly influential handbook on computus, known in modern editions as De temporum ratione. Since the time of Thomas Wright, scholars have debated which of these three Ælfric is referring to in his introduction to DTA, but a close inspection of the text soon indicates that here, as in the preface to the Catholic Homilies, he is being excessively modest about the scope of his sources. He clearly had great respect for Bede, describing him elsewhere as Beda se snotera engla ðeoda lareow. Evoking Bede's name as a point of authority (in G, Beda is written in small capitals in line 5), whilst remaining open to the inclusion of material from other sources, would be entirely consistent with Ælfric's practice in his homiletic works. He perhaps gives a hint in DTA when he reminds us that Bede himself gegaderode of manegra wisra lareowa bocum (5–6). Not surprisingly, however, DTA has often been seen as essentially a patchwork of material derived from the three scientific works of Bede, with a few additions from his commentary on the early chapters of Genesis, the Libri quattuor in principium Genesis. DTA's concise and straightforward style is often more reminiscent of the earlier, and more accessible, DT and DNR, although in terms of content DTR is by far the most heavily used. Godden and Pope agree that, in his homiletic writings, Ælfric did not use DT, although Crawford concluded that he had used all three Bedan scientific works, as well as the commentary on Genesis, in composing the Hexameron. Bede incorporated passages from both DT and DNR into DTR almost verbatim, so it is not always easy to decide which of these works was Ælfric's main source at any particular point.