Princess Irene, Duchess of Aosta
Princess Irene of Greece and Denmark( 13 February 1904 – 15 April 1974) was the fifth child and second daughter of Constantine I of Greece and his wife, the former Princess Sophie of Prussia.
She was a member of the royal families of Greece and Italy.
From 1941 to 1943 she was also officially Queen Consort of Croatia.
Maria, wife of Constantine V
Maria( Greek: Μαρία; died 751) was the second Empress consort of Constantine V of the Roman Empire.
Princess Alexia of Greece and Denmark
Princess Alexia of Greece and Denmark( born 10 July 1965) is the eldest child of Constantine II and Anne- Marie of Denmark, who were king and queen of Greece from 1964 until the abolition of the monarchy in 1973.
Obata Toramori
He was the father of Obata Masamori.
Constantine I of Greece
Constantine I ("Konstantínos I"; – 11 January 1923) was King of Greece from 1913 to 1917 and from 1920 to 1922.
He was commander-in-chief of the Hellenic Army during the unsuccessful Greco-Turkish War of 1897 and led the Greek forces during the successful Balkan Wars of 1912–1913, in which Greece expanded to include Thessaloniki, doubling in area and population.
He succeeded to the throne of Greece on 18 March 1913, following his father's assassination.
His disagreement with Eleftherios Venizelos over whether Greece should enter World War
I led to the National Schism.
Constantine forced Venizelos to resign twice, but in 1917 he left Greece, after threats by the Entente forces to bombard Athens; his second son, Alexander, became king.
After Alexander's death, Venizelos' defeat in the 1920 legislative elections, and a plebiscite in favor of his return, Constantine was reinstated.
He abdicated the throne for the second and last time in 1922, when Greece lost the Greco-Turkish War of 1919–1922, and was succeeded by his eldest son, George II.
Constantine died in exile four months later, in Sicily.
Princess Katherine of Greece and Denmark
Princess Katherine of Greece and Denmark( 4 May 1913 – 2 October 2007), styled in the UK as Lady Katherine Brandram from 1947 till her death, was the third daughter and youngest child of King Constantine I of Greece and Sophia of Prussia.
Prince Nikolaos of Greece and Denmark
Prince Nikolaos of Greece and Denmark( born 1 October 1969) is the third child of Constantine II and Anne- Marie of Denmark, who were the last King and Queen of Greece, reigning from 1964 to 1973.
Marie-Chantal, Crown Princess of Greece
Marie- Chantal, Crown Princess of Greece( Marie- Chantal Claire;" née" Miller; born 17 September 1968) is the wife of Pavlos, Crown Prince of Greece, son of Constantine II of Greece and Anne- Marie of Denmark.
Her husband is the heir apparent to the defunct throne of Greece, as the monarchy was abolished in 1973.
She is a Danish princess by marriage, as her husband is a male- line descendant of Christian IX of Denmark.
Athanasios Miaoulis
Athanasios Miaoulis( 1815 – 7 June 1867) was a Greek military officer and Prime Minister of Greece.
Born in Hydra in 1815 the son of the famous Greek admiral Andreas Miaoulis, from whom he learned his navigation skills.
George I of Greece
George I (Greek:
Γεώργιος Α΄, Geórgios I; 24 December 1845 – 18 March 1913) was King of Greece from 1863 until his assassination in 1913.
Originally a Danish prince, he was born in Copenhagen, and seemed destined for a career in the Royal Danish Navy.
He was only 17 years old when he was elected king by the Greek National Assembly, which had deposed the unpopular former king Otto.
His nomination was both suggested and supported by the Great Powers: the United Kingdom of Great Britain and Ireland, the Second French Empire and the Russian Empire.
He married the Russian grand duchess Olga Constantinovna of Russia in 1867, and became the first monarch of a new Greek dynasty.
Two of his sisters, Alexandra and Dagmar, married into the British and Russian royal families.
King Edward VII and Tsar Alexander III were his brothers-in-law, and King George V, Tsar Nicholas II, King Christian X of Denmark and King Haakon VII of Norway were his nephews.
George's reign of almost 50 years (the longest in modern Greek history) was characterized by territorial gains as Greece established its place in pre-World War
I Europe.
Britain ceded the Ionian Islands peacefully in 1864, while Thessaly was annexed from the Ottoman Empire after the Russo-Turkish War (1877–1878).
Greece was not always successful in its territorial ambitions; it was defeated in the Greco-Turkish War (1897).
During the First Balkan War, after Greek troops had captured much of Greek Macedonia, George was assassinated in Thessaloniki.
Compared with his own long tenure, the reigns of his successors Constantine, Alexander, and George II proved short and insecure.

Question: What is the place of birth of Constantine I Of Greece's father?
Answer: Copenhagen