According to <a href="https://en.wikipedia.org/wiki/Ptolemy" id="mwEQ" rel="mw:WikiLink" title="Ptolemy">Ptolemy</a>, the <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Epoch_(reference_date)" id="mwEg" rel="mw:WikiLink" title="Epoch (reference date)">epoch</a> (origin) of the <a href="https://en.wikipedia.org/wiki/Nabonassar" id="mwEw" rel="mw:WikiLink" title="Nabonassar">Nabonassar</a> Era began at noon on this date.<sup about="#mwt16" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-1"}}' id="cite_ref-1" rel="dc:references" typeof="mw:Extension/ref"><a href="./February_26#cite_note-1" id="mwFA" style="counter-reset: mw-Ref 1;"><span class="mw-reflink-text" id="mwFQ">[1]</span></a></sup> Historians use this to establish the modern <a href="https://en.wikipedia.org/wiki/Anno_Domini" id="mwFg" rel="mw:WikiLink" title="Anno Domini">BC chronology</a> for dating historic events.<sup about="#mwt20" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-2"}}' id="cite_ref-2" rel="dc:references" typeof="mw:Extension/ref"><a href="./February_26#cite_note-2" id="mwFw" style="counter-reset: mw-Ref 2;"><span class="mw-reflink-text" id="mwGA">[2]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-1"><cite about="#mwt13" class="citation book cs1" id="CITEREFHannah2013">Hannah, Robert (2013). <a class="external text" href="https://books.google.com/books?id=qSOSAQAAQBAJ" id="mwBiE" rel="mw:ExtLink nofollow"><i id="mwBiI">Greek and Roman Calendars</i></a>. London: Bloomsbury. p.<span id="mwBiM" typeof="mw:Entity"> </span>94. <a class="mw-redirect" href="./ISBN_(identifier)" id="mwBiQ" rel="mw:WikiLink" title="ISBN (identifier)">ISBN</a><span id="mwBiU" typeof="mw:Entity"> </span><a href="./Special:BookSources/9781849667517" id="mwBiY" rel="mw:WikiLink" title="Special:BookSources/9781849667517"><bdi id="mwBic">9781849667517</bdi></a>.</cite><span about="#mwt13" class="Z3988" id="mwBig" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=Greek+and+Roman+Calendars&amp;rft.place=London&amp;rft.pages=94&amp;rft.pub=Bloomsbury&amp;rft.date=2013&amp;rft.isbn=9781849667517&amp;rft.aulast=Hannah&amp;rft.aufirst=Robert&amp;rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DqSOSAQAAQBAJ&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AFebruary+26"></span></span>