The title of Duke of Ireland was created in 1386 for Robert de Vere, 9th Earl of Oxford, the favorite of King Richard II of England who had previously been created Marquess of Dublin. At this time, only parts of Ireland (the Lordship of Ireland) was under English rule. Despite its name, the Dukedom of Ireland is generally considered to have been one in the Peerage of England, and is the first time that a Ducal title was created for someone who was not a close relative of the King. The Duke fell from favor shortly after receiving the title, which was forfeited in 1388.
Since Henry VIII of England took the title King of Ireland in 1541, Ireland was not used as a dukedom again.
