Tickhill Castle
... that Roger de Busli deliberately built Tickhill Castle directly on the Nottingham-Yorkshire border as he had authority in both?
... that <a href="./Roger_de_Busli" id="mwE1U" rel="mw:WikiLink" title="Roger de Busli">Roger de Busli</a> deliberately built <b id="mwE1Y"><a href="./Tickhill_Castle" id="mwE1c" rel="mw:WikiLink" title="Tickhill Castle">Tickhill Castle</a></b> directly on the <a href="./Nottingham" id="mwE1g" rel="mw:WikiLink" title="Nottingham">Nottingham</a>-<a href="./Yorkshire" id="mwE1k" rel="mw:WikiLink" title="Yorkshire">Yorkshire</a> border as he had authority in both?