The title Earl Mountbatten of Burma was created in the Peerage of the United Kingdom in 1947 for Louis Mountbatten, the last Viceroy of India. The title is the first in over three centuries to allow descent in the female line. The letters patent creating the title specified the "remainder" allowing the title to descend to heirs male, and in default of such issue to his eldest daughter. Lord Mountbatten's eldest daughter Patricia succeeded as Countess Mountbatten upon the former's assassination.
The subsidiary titles of the Countess Mountbatten are: Viscountess Mountbatten of Burma (created 1946) and Baroness Romsey (1947). Both of these titles, in the Peerage of the United Kingdom, have the same special remainder as the Earldom. The title Baron Romsey is the courtesy title for the Countess' eldest son and heir.