765, when the Assyrians for the second time invaded Hadrach, in the neighbourhood of Damascus, their records mention a pestilence, which, both because their armies were then in Syria, and because the plague generally spreads over the whole of Western Asia, may well have been the pestilence mentioned by Amos. In 763 a total eclipse of the sun took place, and is perhaps implied by the ninth verse of his eighth chapter. If this double allusion to pestilence and eclipse be correct, it brings the book down to the middle of the century and the latter half of Jeroboam's long reign. In 755 the Assyrians came back to Hadrach; in 754 to Arpad: with these exceptions Syria was untroubled by them till after 745. It was probably these quiet years in which Amos found Israel _at ease in Zion_.[121] If we went down further, within the more forward policy of Tiglath-Pileser, who ascended the throne in 745 and besieged Arpad from 743 to 740, we should find an occasion for the urgency with which Amos warns Israel that the invasion of her land and the overthrow of the dynasty of Jeroboam will be immediate.[122] But Amos might have spoken as urgently even before Tiglath-Pileser's accession; and the probability that Hosea, who prophesied within Jeroboam's reign, quotes from Amos seems to imply that the prophecies of the latter had been current for some time. Towards the middle of the eighth century--is, therefore, the most definite date to which we are able to assign the Book of Amos. At so great a distance the difference of a few unmarked years is invisible. It is enough that we know the moral dates--the state of national feeling, the personages alive, the great events which are behind the prophet, and the still greater which are imminent. We can see that Amos wrote in the political pride of the latter years of Jeroboam's reign, after the pestilence and eclipse of the sixties, and before the advance of Tiglath-Pileser in the last forties, of the eighth century. A particular year is indeed offered by the title of the book, which, if not by Amos himself, must be from only a few years later:[123] _Words of Amos, which he saw in the days of Uzziah and of Jeroboam, two years before the earthquake_. This was the great earthquake of which other prophets speak as having happened in the days of Uzziah.[124] But we do not know where to place the year of the earthquake, and are as far as ever from a definite date. The mention of the earthquake, however, introduces us to the answer of another of our questions--whether, with all its unity, the Book of Amos reveals any lines of progress, either of event or of idea, either historical or logical.