Incidentally it may be noted that this date has been harmonized with the figure assigned in the margin of some manuscripts as representing the length of tin third dynasty of Berossus. It has usually been held that his sixth dynasty ended with the predecessor of Nabonassar upon the throne of Babylon, and that the following or seventh dynasty would have begun in 747 B.C. But it has been pointed out that, after enumerating the dynasties II.-VI., Eusebius goes on to say that after these rulers came a king of the Chaldeans whose name was Phulus[71]; and this phrase has been explained as indicating that the sixth dynasty of Berossus ended at the same point as the Ninth Babylonian Dynasty, in 732 B.C., that is to say, with the reign of Nabû-shum-ukîn, the contemporary of Tiglath-pileser IV., whose original name of Pulu is preserved in the Babylonian List of Kings. Thus the seventh dynasty of Berossus would have begun with the reign of the usurper Ukîn-zêr, who was also the contemporary of Tiglath-pileser.[72] On this supposition the figure "forty-eight," which occurs in the margin of certain manuscripts of the Armenian version of Eusebius,[73] may be retained for the number of years assigned by Berossus to his third dynasty.[74] A further confirmation of the date 2232 B.C. for the beginning of the historical period of Berossus has been found in a statement derived from Porphyrins, to the effect that, according to Callisthenes, the Babylonian records of astronomical observations extended over a period of 1903 years down to the time of Alexander of Macedon.[75] Assuming that the reading 1903 is correct, the observations would have extended back to 2233 B.C., a date differing by only one year from that obtained for the beginning of Berossus' historical dynasties.