I usually date Hezekiah 727/726-698/697 BC. However, there are four modestly reasonable (though all disputable) reasons to date Hezekiah to 716/15-687/6 BC. One is 2 Kings 18:13. The other is the fact not one of Sennacherib’s post-797 BC inscriptions mentions Hezekiah’s death. Another is the existence of an Ahaz bulla, if it is assumed even modestly widespread literacy among even the elite could not have begun in Judah before 720 BC. The last is mentioned by GM Grena, who, assuming all lmlk impressions date to the reign of Hezekiah, points out there are about as many pre-Revolt lmlk handles as there are post-Revolt handles. However, while a purely non-Biblical view could quite easily accommodate a late reign for Hezekiah, I find it extraordinarily difficult to not date Hezekiah’s reign to 727/726-698/697 BC considering the Biblical data.