Prince Frederick of Württemberg
... that Prince Frederick of Württemberg attained the rank of Rittmeister 2nd class in the Army of Württemberg by the age of 15?
... that <b id="mwD1Q"><a href="./Prince_Frederick_of_Württemberg" id="mwD1U" rel="mw:WikiLink" title="Prince Frederick of Württemberg">Prince Frederick of Württemberg</a></b> attained the rank of <a class="mw-redirect" href="./Rittmeister" id="mwD1Y" rel="mw:WikiLink" title="Rittmeister">Rittmeister</a> 2nd class in the <a href="./Army_of_Württemberg" id="mwD1c" rel="mw:WikiLink" title="Army of Württemberg">Army of Württemberg</a> by the age of 15?