In line with royal tradition, the names remained secret until the ceremony at the Holmen church in downtown Copenhagen.
Australian-born /*Crown Princess Mary*/ gave birth to the twins on Jan. 8. She and /*Crown Prince Frederik*/ have two other children: 5-year-old Christian and 3-year-old Isabella.
About 300 people attended the ceremony, including Fredrik's brother /*Prince Joachim*/ and their parents /*Queen Margrethe*/ and /*Prince Henrik.*/ Mary's father /*John Donaldson*/ was also there with his wife, /*Susan Elizabeth.*/
The baby prince was given three other names - Frederik, Minik and Alexander - while his twin sister was named Josephine Sophia Ivalo Mathilda.
Minik and Ivalo are Greenlandic names. The crown prince has a close relationship to the semiautonomous Danish territory, and has traveled dozens of time to the Arctic island.
After the ceremony, which was broadcast live on Danish TV, the royals and guests headed for the Amalienborg Palace, home of the royal family, for a reception, and family and friends were later scheduled to attend a banquet dinner at the downtown Renaissance-style castle.
