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 was born at Frederiksborg Castle in Denmark on 12 April 1577 as the third child and eldest son of King Frederick II of Denmark–Norway and Sofie of Mecklenburg-Schwerin. He was descended, through his mother's side, from king John of Denmark , and was thus the first descendant of King John to assume the crown since the deposition of King Christian II .
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 II (1 July 1481 – 25 January 1559) was a Scandinavian monarch under the Kalmar Union who reigned as King of Denmark and Norway, from 1513 until 1523, and Sweden from 1520 until 1521. From 1513 to 1523, he was concurrently Duke of Schleswig and Holstein in joint rule with his uncle Frederick .
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 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 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.