Prince Nicholas of Greece and Denmark, of the Glücksburg branch of the House of Oldenburg, was the fourth child and third son of King George I of Greece, and of Queen Olga. He was known as "Greek Nicky" within the family to distinguish him from his cousin Emperor Nicholas II of Russia. Prince Nicholas was a talented painter, often signing his works as "Nicolas Leprince."

Olga Constantinovna of Russia was Queen of Greece as the wife of King George I. She was briefly the regent of Greece in 1920.