Merthen
... that Richard, 1st Earl of Cornwall swapped Merthen for Tintagel Castle?
... that <a class="mw-redirect" href="./Richard,_1st_Earl_of_Cornwall" id="mwBU8" rel="mw:WikiLink" title="Richard, 1st Earl of Cornwall">Richard, 1st Earl of Cornwall</a> swapped <b id="mwBVA"><a href="./Merthen_Manor" id="mwBVE" rel="mw:WikiLink" title="Merthen Manor">Merthen</a></b> for <a href="./Tintagel_Castle" id="mwBVI" rel="mw:WikiLink" title="Tintagel Castle">Tintagel Castle</a>?