In his <a href="https://en.wikipedia.org/wiki/Apostolic_constitution" id="mwRw" rel="mw:WikiLink" title="Apostolic constitution">Apostolic constitution</a> <i id="mwSA"><a href="https://en.wikipedia.org/wiki/Ineffabilis_Deus" id="mwSQ" rel="mw:WikiLink" title="Ineffabilis Deus">Ineffabilis Deus</a></i>, <a href="https://en.wikipedia.org/wiki/Pope_Pius_IX" id="mwSg" rel="mw:WikiLink" title="Pope Pius IX">Pope Pius IX</a> proclaims the <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Dogmatic_definition" id="mwSw" rel="mw:WikiLink" title="Dogmatic definition">dogmatic definition</a> of <a href="https://en.wikipedia.org/wiki/Immaculate_Conception" id="mwTA" rel="mw:WikiLink" title="Immaculate Conception">Immaculate Conception</a>, which holds that the <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Blessed_Virgin_Mary" id="mwTQ" rel="mw:WikiLink" title="Blessed Virgin Mary">Blessed Virgin Mary</a> was conceived free of <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Original_Sin" id="mwTg" rel="mw:WikiLink" title="Original Sin">Original Sin</a>.