Princess Irene of Greece and Denmark 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.

Constantine I was King of Greece from 18 March 1913 to 11 June 1917 and from 19 December 1920 to 27 September 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. The eldest son of George I of Greece, he succeeded to the throne following his father's assassination in 1913.