Frederick Ferdinand, Hereditary Prince of Denmark was grandson of King Frederick V and heir presumptive to the throne from 1848 until his death. Had he livedmonths more, he would have outlived his nephew, King Frederick VII, and become King of Denmark.
Prince Ferdinand was born at Christiansborg Palace in Copenhagen onNovember 1792 as the youngest child of Frederick, Hereditary Prince of Denmark and Norway and Sophie Frederikke of Mecklenburg, thus being a grandson of late King Frederick V of Denmark and Norway.
Source: Wikipedia