Unfortunately, none of the above theories of how many invasions happened, in any way solves the problem of chronology regarding Sennacherib being called king of Assyria and having his first or only campaign in Hezekiahs 14 year, the bible provides a total of 133 years 6 months and 10 days, or roughly 134 years between the deportation of Judah in 586 and the deportation of the Northern kingdom of Israel which is thus placed in 720 (a one year variance with modern scholarship).Since these two were brothers and since the firstborn was the normal heir to the throne, some time must have passed for Jehoiakim to reach an older age upon his ascension than that of his older brother Jehoahaz, when he was placed on the throne.Firstly due to Merodach-baladan being in power as king of Babylon, secondly the promise to save Jerusalem prophesied (Isaiah 38:6) to Hezekiah and thirdly due to the quantity of Hezekiahs treasure at the time indicating that Sennacherib had not yet taken it from him (Gallagher p144 note 5).
This shall be a sign to you: You shall eat this year such as grows of itself, And in the second year what springs from the same; Also in the third year sow and reap, Plant vineyards and eat the fruit of them Assuming that was the understanding the Jews of Hezekiahs time had of their own history, regardless of its accuracy (which is debated by some scholars), they would have considered 702 BC as a Jubilee year and 703 as a sabbatical year.
The problem with the idea that the bible describes two invasions is that while this might be possible in the account in Kings, the other records (Isaiah and Chronicles) seem to make the two events into one.
Ashurnadin-shum, the son of Sennacherib, was then crowned king of Babylon.
A campaign into Cilicia and Cappadocia followed In my third campaign I marched against Hatti.
The commonly accepted Assyrian chronology gives him about 16 years (ABD IV p744) One solution might be to allow for a co-regency between Sennacherib and Sargon.
However direct proof for such is lacking, just as it is for the claim of a co-regency between Hezekiah and Ahaz.The difference between their birthdates need not be great if they were born to different wives.For they could not keep it at the regular time, because a sufficient number of priests had not consecrated themselves, nor had the people gathered together at Jerusalem So they resolved to make a proclamation throughout all Israel, from Beersheba to Dan The placement of Hezekiahs Passover of his first year in the period preceding the deportation of the Northern tribes is internal evidence that he was in power before 721BC and thus supports the other straight forward claims to such by the biblical writers.Some scholars, however, have argued that if the siege of Lachish was considered important enough to warrant the fashioning of a series of sculptures, it would have certainly been deemed important enough to have been mentioned in the Annals.Thus according to Honor, they must consider the Biblical account of the attack on Lachish to be the gloss of a later editor or for Lachish to have been attacked twice by Sennacherib, the first time he won easily and thus it wasnt important enough to record and the second time Lachish resisted harder and was only taken after a long siege.Upon close investigation one will realize that those 10 years will have to be subtracted from Manassehs and/or Josiahs reigns, for the other kings who reigned after Hezekiah have reigns that cannot be adjusted to be shorter, at least not by more than a few months.