Having received a letter during the Lenten synod of 14–20 February demanding that he abdicate,<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_22#cite_note-1" id="mwEQ" style="counter-reset: mw-Ref 1;"><span class="mw-reflink-text" id="mwEg">[1]</span></a></sup> <a href="https://en.wikipedia.org/wiki/Pope_Gregory_VII" id="mwEw" rel="mw:WikiLink" title="Pope Gregory VII">Pope Gregory VII</a> excommunicates <a href="https://en.wikipedia.org/wiki/Henry_IV,_Holy_Roman_Emperor" id="mwFA" rel="mw:WikiLink" title="Henry IV, Holy Roman Emperor">Henry IV, Holy Roman Emperor</a>.<sup about="#mwt23" 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_22#cite_note-2" id="mwFQ" style="counter-reset: mw-Ref 2;"><span class="mw-reflink-text" id="mwFg">[2]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-1"><cite about="#mwt13" class="citation book cs1" id="CITEREFBlumenthal2001">Blumenthal, Uta-Renate (2001). "Gregory VII". In Jeep, John M. (ed.). <a class="external text" href="https://books.google.com/books?id=p4uHav3mZLsC" id="mwBvI" rel="mw:ExtLink nofollow"><i id="mwBvM">Medieval Germany: An Encyclopedia</i></a>. New York: Garland Publishing. p.<span id="mwBvQ" typeof="mw:Entity"> </span>310. <a class="mw-redirect" href="./ISBN_(identifier)" id="mwBvU" rel="mw:WikiLink" title="ISBN (identifier)">ISBN</a><span id="mwBvY" typeof="mw:Entity"> </span><a href="./Special:BookSources/9781138062658" id="mwBvc" rel="mw:WikiLink" title="Special:BookSources/9781138062658"><bdi id="mwBvg">9781138062658</bdi></a>. <a class="external text" href="https://web.archive.org/web/20220109155448/https://books.google.com/books?id=p4uHav3mZLsC" id="mwBvk" rel="mw:ExtLink nofollow">Archived</a> from the original on 2022-01-09<span class="reference-accessdate" id="mwBvo">. Retrieved <span class="nowrap" id="mwBvs">2022-02-14</span></span>.</cite><span about="#mwt13" class="Z3988" id="mwBvw" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&amp;rft.genre=bookitem&amp;rft.atitle=Gregory+VII&amp;rft.btitle=Medieval+Germany%3A+An+Encyclopedia&amp;rft.place=New+York&amp;rft.pages=310&amp;rft.pub=Garland+Publishing&amp;rft.date=2001&amp;rft.isbn=9781138062658&amp;rft.aulast=Blumenthal&amp;rft.aufirst=Uta-Renate&amp;rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3Dp4uHav3mZLsC&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AFebruary+22"></span></span>