Günther Sizzo, Prince of Schwarzburg was the head of the House of Schwarzburg and pretender to the principalities of Schwarzburg-Rudolstadt and Schwarzburg-Sondershausen.

Morganatic marriage, sometimes called a left-handed marriage, is a marriage between people of unequal social rank, which in the context of royalty or other inherited title prevents the principal's position or privileges being passed to the spouse, or any children born of the marriage. The concept is most prevalent in German-speaking territories and countries most influenced by the customs of the German-speaking realms.