Princess Frederica Louise Thyra Victoria Margaret Sophie Olga Cecily Isabelle Christina of Hanover, Duchess of Brunswick-Lüneburg, Princess of Great Britain and Ireland, was born on April 18, 1917 in Blankenburg, Prussia, part of the German Empire. She was the only daughter of Prince Ernst Augustus of Hanover, Duke of Brunswick-Lüneburg, and Princess Victoria Louise of Prussia. Through her mother, Princess Frederica was a granddaughter of Kaiser Wilhelm II of Germany.
In 1937, Princess Frederica accepted the marriage proposal of Crown Prince Paul of Greece. Paul was Frederica's first cousin once-removed: his mother, Queen Sophia of Greece, was the sister of Frederica's grandfather, Kaiser Wilhelm. Paul and Frederica were also descendants of both Britain's Queen Victoria and King Christian IX of Denmark. They were married in Athens in January 1938. She gave birth to their first child, Princess Sophia of Greece, in November of that year. Their first son, Prince Constantine of Greece, was born in June 1940, and their last child, Princess Irene, arrived in 1942.
As Crown Princess of Greece, Frederica was praised for her youthful exuberance and vivacious character, but initially gained some criticism concerning her German heritage. Crown Prince Paul became king in 1947, and for the first years of his reign Greece was plagued by civil war. King Paul and Queen Frederica worked tirelessly to aid their war-torn subjects. Queen Frederica set up the Queen's Camps to shelter and feed displaced child refugees of the war, and also braved dangerous battlefields to pay visits to soldiers. Despite her charitable efforts, Queen Frederica could never completely escape criticism. Her German heritage remained a source of contention for many Greeks, particularly after World War II, and her active political involvement also garnered detractors.
King Paul died suddenly in March 1964, and Queen Frederica's only son ascended the throne as King Constantine II. As queen mother, Frederica curtailed many of her royal duties in favor of her son's new wife, Queen Anne-Marie. In December 1967, after King Constantine unsuccessfully attempted to overthrow the military regime that had seized control of the Greek government earlier that year, Queen Frederica fled Greece into exile with her son, his children and her daughter Irene.
In exile, Queen Frederica made numerous trips to India and became interested in eastern mysticism. She also spent her time visiting her growing brood of grandchildren. While her son Constantine went to live in a mansion in the outskirts of London, Frederica and Princess Irene lived primarily in Madrid with her daughter Sophia's family.
Queen Frederica died on February 6, 1981 at a hospital in Madrid of complications resulting from eye surgery (presumably done to remove cataracts). The Greek government permitted her family to bury her at the royal family's residence in Tatoi, near Athens, alongside her late husband. Frederica's son, King Constantine, and his family were allowed to attend the funeral, on the condition that they left Greece immediately after the burial.
Queen Frederica's eldest daughter is Queen Sofia of Spain, wife of King Juan Carlos. Frederica's eight grandchildren are - Infanta Elena of Spain, Infanta Cristina of Spain, Felipe, Prince of Asturias; Princess Alexia of Greece, Crown Prince Pavlos of Greece, Prince Nikolaos of Greece, Princess Theodora of Greece, and Prince Philippos of Greece.