The British, Greek, Russian and Danish royal families in 1882 at Fredensborg Palace in Denmark.
The painting is of “Europe’s mother and father in law”, King Christian 9 of Denmark and Queen Louise, with their children, son and daughter in laws and grandchildren.
Queen Alexandra of the United Kingdom (oldest daughter of King Christian and Queen Louise) stands to the left with her husband King Edward 7 of the United Kingdom sitting on a chair, behind her is Crown Princess Thyra of Hanover (youngest daughter of King Christian and Queen Louise) holding her child, in front left is Queen Louise of Denmark on a couch with her husband King Christian 9 of Denmark, in standing center is Empress Maria Feodorovna (second oldest daughter of King Christian and Queen Louise) and her husband Emperor Alexander 3 of Russia. The Lady seated at right in a red dress is Princess Marie d’Orléans of Denmark (daughter in law of King Christian and Queen Louise) , while the girl to her right is Princess Alexandra of Greece (granddaughter of King Christian and Queen Louise) standing beside her mother, Queen Olga of Greece (daughter in law of King Christian and Queen Louise). Behind Princess Marie d’Orléans is her husband Prince Valdemar of Denmark (youngest son of King Christian and Queen Louise) and King Géorgios 1 of Greece (second oldest son of King Christian and Queen Louise).
Note: I am not sure why the oldest son Crown Prince Frederik of Denmark and his family are not in the painting. It seems rather strange.
