Namesakes
Maria Feodorovna of Russia
(middle name Frederikke) (f) 1847-1928 
Other Royalty 1853-1866; 1881-1894 Denmark; Russia (princess/empress consort)
Ingeborg of Denmark
(middle name Frederikke) (f) 1878-1958
Other Royalty 1878-1897; 1897-1958 Denmark; Sweden (princess)
Feodora of Denmark
(middle name Frederikke) (f) 1910-1975
Other Royalty 1910-1975 Denmark (princess)