Janusz III Mazowiecki
...that in 1526, with the heirless death of Janusz III Mazowiecki, last of the Masovian Piasts, the Duchy of Masovia was reunited with Poland?
...that in 1526, with the heirless death of <b id="mwCw8"><a class="mw-redirect" href="./Janusz_III_Mazowiecki" id="mwCxA" rel="mw:WikiLink" title="Janusz III Mazowiecki">Janusz III Mazowiecki</a></b>, last of the <a class="mw-redirect" href="./Masovia" id="mwCxE" rel="mw:WikiLink" title="Masovia">Masovian</a> <a href="./Piast_dynasty" id="mwCxI" rel="mw:WikiLink" title="Piast dynasty">Piasts</a>, the <a href="./Duchy_of_Masovia" id="mwCxM" rel="mw:WikiLink" title="Duchy of Masovia">Duchy of Masovia</a> was <a class="mw-redirect" href="./Fragmentation_of_Poland" id="mwCxQ" rel="mw:WikiLink" title="Fragmentation of Poland">reunited</a> with <a href="./Poland" id="mwCxU" rel="mw:WikiLink" title="Poland">Poland</a>?