With the <a href="https://en.wikipedia.org/wiki/Papal_bull" id="mwPg" rel="mw:WikiLink" title="Papal bull">papal bull</a> <i id="mwPw"><a href="https://en.wikipedia.org/wiki/Inter_gravissimas" id="mwQA" rel="mw:WikiLink" title="Inter gravissimas">Inter gravissimas</a></i>, <a href="https://en.wikipedia.org/wiki/Pope_Gregory_XIII" id="mwQQ" rel="mw:WikiLink" title="Pope Gregory XIII">Pope Gregory XIII</a> announces the <a href="https://en.wikipedia.org/wiki/Gregorian_calendar" id="mwQg" rel="mw:WikiLink" title="Gregorian calendar">Gregorian calendar</a>.<sup about="#mwt45" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-7"}}' id="cite_ref-7" rel="dc:references" typeof="mw:Extension/ref"><a href="./February_24#cite_note-7" id="mwQw" style="counter-reset: mw-Ref 7;"><span class="mw-reflink-text" id="mwRA">[7]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-7"><cite about="#mwt42" class="citation book cs1" id="CITEREFWigelsworth2006">Wigelsworth, Jeffrey R. (2006). <a class="external text" href="https://books.google.com/books?id=VPDqnGGHpHYC" id="mwBvA" rel="mw:ExtLink nofollow"><i id="mwBvE">Science and Technology in Medieval European Life</i></a>. Westport, Conn.: Greenwood Press. p.<span id="mwBvI" typeof="mw:Entity"> </span>135. <a class="mw-redirect" href="./ISBN_(identifier)" id="mwBvM" rel="mw:WikiLink" title="ISBN (identifier)">ISBN</a><span id="mwBvQ" typeof="mw:Entity"> </span><a href="./Special:BookSources/9780313337543" id="mwBvU" rel="mw:WikiLink" title="Special:BookSources/9780313337543"><bdi id="mwBvY">9780313337543</bdi></a>. <a class="external text" href="https://web.archive.org/web/20220224154100/https://books.google.com/books?id=VPDqnGGHpHYC" id="mwBvc" rel="mw:ExtLink nofollow">Archived</a> from the original on 2022-02-24<span class="reference-accessdate" id="mwBvg">. Retrieved <span class="nowrap" id="mwBvk">2021-02-24</span></span>.</cite><span about="#mwt42" class="Z3988" id="mwBvo" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=book&amp;rft.btitle=Science+and+Technology+in+Medieval+European+Life&amp;rft.place=Westport%2C+Conn.&amp;rft.pages=135&amp;rft.pub=Greenwood+Press&amp;rft.date=2006&amp;rft.isbn=9780313337543&amp;rft.aulast=Wigelsworth&amp;rft.aufirst=Jeffrey+R.&amp;rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DVPDqnGGHpHYC&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AFebruary+24"></span></span>