Princess Anne attends the opening of an exhibition celebrating the 800th anniversary of the Magna Carta at the Library of Congress in Washington, DC, November 6, 2014.

The British Princess Royal, Princess Anne speaks during the opening of an exhibition celebrating the 800th anniversary of the Magna Carta at the Library of Congress in Washington, DC, 06.11.2014.

The British Princess Royal, Princess Anne arrives for the opening of an exhibition celebrating the 800th anniversary of the Magna Carta at the Library of Congress in Washington, DC, 06.11.2014.

The British Princess Royal, Princess Anne, stands alongside her husband, Timothy Laurence, during the opening of an exhibition celebrating the 800th anniversary of the Magna Carta at the Library of Congress in Washington, DC, 06.11.2014.

The British Princess Royal, Princess Anne (2nd R), sits alongside her husband, Timothy Laurence (2nd L), James Billington (R), Librarian of Congress and his wife, Marjorie Billington (L), during the opening of an exhibition celebrating the 800th anniversary of the Magna Carta at the Library of Congress in Washington, DC, 06.11.2014.

The British Princess Royal, Princess Anne, sits alongside her husband, Timothy Laurence, during the opening of an exhibition celebrating the 800th anniversary of the Magna Carta at the Library of Congress in Washington, DC, 06.11.2014.

Britain's Princess Anne talks with The Librarian of Congress Dr. James Billington during the public opening ceremony of a new Library of Congress exhibit, Magna Carta: Muse and Mentor, 06.11.2014, in Washington, DC

Britain's Princess Anne, center, arrives for the public opening ceremony of a new Library of Congress exhibit, Magna Carta: Muse and Mentor, Thursday, 06.11.2014, in Washington, DC

Britain's Princess Anne listens during the public opening ceremony of a new Library of Congress exhibit, Magna Carta: Muse and Mentor, 06.11.2014, in Washington, DC