Of the sources for the reign of Sennacherib (705-686), [Footnote: The only fairly complete collection of sources for the reign is still Smith-Sayce, _History of Sennacherib_, 1878, though nearly all the data needed for a study of the Annals are given by Bezold, KB. II. 80 ff. Extracts, Rogers, 340 ff. Cf. also Olmstead, _Western Asia in the reign of Sennacherib, Proceedings of Amer. Historical Assn._, 1909, 94 ff.] the chief is the Annals, added to at intervals of a few years, and so existing in several editions. As usual, the latest of these, the Taylor inscription, has been accorded the place of honor, so that the earliest edition, the so called Bellino Cylinder, can be called by a well known historian "a sort of duplicate of" the Taylor inscription. [Footnote: Maspero, _Histoire_, III. 273 _n. 1._] As we have seen repeatedly, the exact reverse should be our procedure, though here, as in the case of Ashur nasir apal, the evil results in the writing of history are less serious than in the case of most reigns. This is due to the unusual circumstances that, with comparatively few exceptions, there was little omission or addition of the earlier data. Regularly, the new edition simply added to the old, and, as a result, the form of the mass of clay on which these Annals were written changes with the increased length of the document, the earlier being true cylinders, while the latter are prisms. [Footnote: King, _Cuneiform Texts_, XXVI. 7 f.] At the same time that the narrative of military events was lengthened, the account of the building operations followed suit. A serious defect is the fact that these documents are dated, not by years, but by campaigns, with the result that there are serious questions in chronology. The increase in the number of our editions, however, has solved many of these, as the date of the campaign can now usually be fixed by observing in which dated document it last occurs.