Following the approach of Wellhausen, another set of calculations shows it is probable that Hezekiah did not ascend the throne before 722 BCE. By Albright's calculations, Jehu's initial year was 842 BC; and between it and Samaria's destruction the "Books of Kings" give the total number of the years the kings of Israel ruled as 143 7/12, while for the kings of Judah the number is 165. This discrepancy, amounting in the case of Judah to 45 years (165−120), has been accounted for in various ways; each of those positions must allow for Hezekiah's first six years to have fallen before 722 BCE. (However, Hezekiah beginning to reign before 722 BCE is consistent with a co-regency of Ahaz and Hezekiah from 729 BC.) Nor is it clearly known how old Hezekiah was when called to the throne; although states that he was twenty-five years of age, his father died at the age of thirty-six () and it is not likely that Ahaz had a son at the age of eleven. Hezekiah's son Manasseh ascended the throne twenty-nine years later, at the age of twelve. This places his birth in the seventeenth year of his father's reign, suggesting Hezekiah's age as forty-two, if he was twenty-five at his ascension. It is more probable that Ahaz was twenty-one or twenty-five when Hezekiah was born (suggesting an error in the text), and that the latter was thirty-two at the birth of his son and successor, Manasseh.