Treaty of Vilnius (1561)
... that by the Treaty of Vilnius (1561), Gotthard Kettler exchanged his office as Grand Master of the Livonian Order for that of a duke and Royal administrator?
... that by the <b id="mwAiE"><a href="./Treaty_of_Vilnius_(1561)" id="mwAiI" rel="mw:WikiLink" title="Treaty of Vilnius (1561)">Treaty of Vilnius (1561)</a></b>, <a href="./Gotthard_Kettler" id="mwAiM" rel="mw:WikiLink" title="Gotthard Kettler">Gotthard Kettler</a> exchanged his office as <a class="mw-redirect" href="./Grand_Master_(order)" id="mwAiQ" rel="mw:WikiLink" title="Grand Master (order)">Grand Master</a> of the <a href="./Livonian_Order" id="mwAiU" rel="mw:WikiLink" title="Livonian Order">Livonian Order</a> for that of a <a href="./Duchy_of_Courland_and_Semigallia" id="mwAiY" rel="mw:WikiLink" title="Duchy of Courland and Semigallia">duke</a> and Royal administrator?