Irene of Greece, Duchess of Aosta was the was the fifth child and second daughter of Constantine I of Greece and his wife, the former Princess Sophie of Prussia. By her mother she was a great-granddaughter of Queen Victoria.
child of Princess Victoria & German Emperor and King of Prussia Frederick III & wife of Constantine I "Tino" of Greece, King of the Hellenes Sophia of Prussia (Sophie Dorothea Ulrike Alice "Sossy") Queen of Greece.
Princess Sophie of Prussia (1870-1932) was a daughter of Princess Royal Victoria of the U.K. and her husband, the future King Frederick III of Prussia. Sophie was the seventh of eight children born in the royal family of Prussia. Sophie married her cousin, the crown prince of Greece, later King Constantine I. Sophie and Constantine had a tumultuous life but a happy marriage with six children.
Two of Kaiser Wilhelm II's sisters, Princess Margaret of Prussia and husband Prince Friedrich Karl of Hesse-Kassel (seated) with Margaret's sister, Princess Sophie and her husband Constantine I of Greece (standing).