German Prince
The terms German Prince or German Princess are often used to refer to members of royalty that were from a German state. Today Germany is one nation, but until 1914, Germany and Central Europe were ruled over by a large number of independent states. Until World War I, the term German could have referred to peoples from areas of what is today the states Germany, Poland, Belgium, Luxembourg, Czech Republic, Slovakia, Austria, and even Croatia, and the Netherlands. From 1815 to 1860 this number was 35 separate German sovereign states (including Prussia and Austria) plus another 4 free  cities, who together formed the German Confederation. Prior to 1789 there were over 300 independent sovereign states and thousands of other bishoprics, lordships, and free cities that made up the Holy Roman Empire. Why use Germans? When the term German Prince or Princess is used, it is referring to a member of one of the many ruling sovereign houses of the Central Europe region. They were often used as suitable marriage candidates, simply due to the fact there were so many of them. Also, as all of the European royalty were related, it helped to use a German prince/princess  to keep the marriage "in the family", so to speak, or sometimes the opposite: to broaden the gene pool. The only other area of Europe that was close to be being ruled over by so many different sovereign states was Italy which after 1815 was made up of at least 11 different states, with the rest of Europe being ruled over by large states.