The dating and sequence of Hittite kings is compiled by scholars from fragmentary records, supplemented by the finds in Ḫattuša and other administrative centers of cuneiform tablets and more than 3,500 seal impressions providing the names, titles, and sometimes ancestry of Hittite kings and officials. Given the nature of the source evidence, reconstructions vary among scholars, and the dating or even existence, relationships and sequence of some kings is disputed at several point within Hittite history. The list below indicates instances of such debates, with references.