Prince Leopold
... that a year after winning the 1816 Derby Stakes, Prince Leopold was castrated for poor behaviour?
... that a year after winning the 1816 <a href="./Epsom_Derby" id="mwBdQ" rel="mw:WikiLink" title="Epsom Derby">Derby Stakes</a>, <b id="mwBdU"><a href="./Prince_Leopold_(horse)" id="mwBdY" rel="mw:WikiLink" title="Prince Leopold (horse)">Prince Leopold</a></b> was <a href="./Castration#Veterinary_practice" id="mwBdc" rel="mw:WikiLink" title="Castration">castrated</a> for poor behaviour?