Reims Gospel
... that most of French kings of the Bourbon era took oath on the Reims Gospel, a medieval book written in Old Church Slavonic languages?
... that most of <a href="./List_of_French_monarchs" id="mwCF4" rel="mw:WikiLink" title="List of French monarchs">French kings</a> of the <a href="./House_of_Bourbon" id="mwCF8" rel="mw:WikiLink" title="House of Bourbon">Bourbon era</a> took oath on the <b id="mwCGA"><a href="./Reims_Gospel" id="mwCGE" rel="mw:WikiLink" title="Reims Gospel">Reims Gospel</a></b>, a medieval book written in <a href="./Old_Church_Slavonic" id="mwCGI" rel="mw:WikiLink" title="Old Church Slavonic">Old Church Slavonic languages</a>?