Peerage of England
The ranks of the English peerage are, in descending order, Duke, Marquess, Earl, Viscount, and Baron. While most newer English peerages descend only in the male line, many of the older ones (particularly older baronies) can descend through females. Under English inheritance law all daughters are co-heirs, so many older English peerage titles have fallen into abeyance between various female co-heirs.
Baron de Ros
Baron de Ros (pronounced "Roose") is the premier baron in the Peerage of England, created in 1288/89 for William de Ros, with precedence to 24 December 1264. (The spelling of the title and of the surname of the original holders has been rendered differently in various texts. The word "Ros" is sometimes spelt "Roos", and the word "de" is sometimes dropped.) "Premier baron" is a designation and status awarded to the holder of the most ancient extant barony of the Peerage of England. The present premier baron is Baron de Ros. Before the Dissolution of the Monasteries the Prior of the Order of St John in England was deemed premier baron.