Viscount Rhondda, of Llanwern in the County of Monmouthshire, was a title in the Peerage of the United Kingdom. It was created in 1918 for the Welsh businessman and Liberal politician David Alfred Thomas, with special remainder to his daughter Margaret. Thomas had already been created Baron Rhondda, of Llanwern in the County of Monmouthshire, in 1916, with remainder to the heirs male of his body. The barony became extinct on his death in 1918, whereas he was succeeded in the viscountcy according to the special remainder by his daughter Margaret. On her death in 1958 this title became extinct as well. The Peerage of the United Kingdom comprises most peerages created in the United Kingdom of Great Britain and Ireland after the Act of Union in 1801. ... 1918 was a common year starting on Tuesday of the Gregorian calendar (see link for calendar) or a common year starting on Wednesday of the Julian calendar. ... 1918 was a common year starting on Tuesday of the Gregorian calendar (see link for calendar) or a common year starting on Wednesday of the Julian calendar. ... 1958 was a common year starting on Wednesday of the Gregorian calendar. ...
While the ranks of baron and earl perhaps predate the Peerage itself, the ranks of duke and marquess were not introduced in England until the fourteenth century.
Ecclesiastical dignitaries and the greater barons were summoned by a writ of summons issued directly from the King, while lesser barons were summoned through the local sheriffs.
In some cases, a baron who held a dignity created by a writ of summons was created an Earl, and the two dignities later separated, the barony devolving upon the heir-general, and the earldom to an heir-male.