Friedrich Ferdinand, Duke of Schleswig Holstein
Friedrich Ferdinand of SchleswigHolsteinSonderburgGlcksburg was the fourth Duke of SchleswigHolsteinSonderburgGlcksburg and became Duke of SchleswigHolstein in 1931.
Friedrich Ferdinand was born in Kiel, Duchy of Holstein, the eldest son of Friedrich, Duke of SchleswigHolsteinSonderburgGlcksburg and Princess Adelheid of SchaumburgLippe and a nephew of Christian IX of Denmark. Friedrich Ferdinand succeeded to the headship of the House of SchleswigHolsteinSonderburgGlcksburg and title duke upon the death of his father onNovember 1885. When the Head of the House of SchleswigHolsteinSonderburgAugustenburg Albert, Duke of SchleswigHolstein died onApril 1931, Friedrich Ferdinand became the Head of the House of Oldenburg and inherited the title Duke of SchleswigHolstein.
Source: Wikipedia