Christian X quickly realized that Denmark was in an impossible position. Its territory and population were far too small to hold out against Germany for any sustained period of time. Its flat land would have resulted in it being easily overrun by German panzers ; Jutland , for instance, would have been overrun in short order by a panzer attack from Schleswig-Holstein immediately to the south.
Christian IX was born on 8 April 1818 at the residence of his maternal grandparents, Gottorf Castle, near the town of Schleswig in the Duchy of Schleswig. Born as a prince of Schleswig-Holstein-Sonderburg-Beck, he was the fourth son of Friedrich Wilhelm, Duke of Schleswig-Holstein-Sonderburg-Beck, and Princess Louise Caroline of Hesse-Kassel.
Christian VIII (18 September 1786 – 20 January 1848) was King of Denmark from 1839 to 1848 and, as Christian Frederick, King of Norway in 1814.  Christian Frederick was the eldest son of Hereditary Prince Frederick , a younger son of King Frederick V of Denmark and Norway.
Christian V (15 April 1646 – 25 August 1699) was king of Denmark and Norway from 1670 until his death in 1699.. Well-regarded by the common people, he was the first king anointed at Frederiksborg Castle chapel as absolute monarch since the decree that institutionalized the supremacy of the king in Denmark-Norway.
Christian X. – gebürtig Prinz Christian Carl Frederik Albert Alexander Vilhelm von Dänemark und Island – (* 26. September 1870 auf Schloss Charlottenlund , Gentofte ; † 20. April 1947 in Schloss Amalienborg , Kopenhagen ) aus dem Haus Schleswig-Holstein-Sonderburg-Glücksburg war von 1912 bis 1947 König von Dänemark sowie als Kristján X von 1918 bis 1944 König von Island .
Christian I was born in February 1426 in Oldenburg in Northern Germany as the eldest son of Count Dietrich of Oldenburg by his second wife, Helvig of Holstein (died 1436). Christian had two younger brothers, Maurice (1428–1464) and Gerhard (1430–1500), and one sister Adelheid. 
Christian VI (30 November 1699 – 6 August 1746) was King of Denmark and Norway from 1730 to 1746. The eldest surviving son of Frederick IV and Louise of Mecklenburg-Güstrow , he is considered one of Denmark-Norway 's more anonymous kings, but he was a skilled politician, best known for his authoritarian regime.