The titles 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. 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.
GLOUCESTER, THOMAS OF WOODSTOCK, DUKE OF (1355-1397), seventh and youngest son of the English king Edward III., was born at Woodstock on the 7th of January 1355.
He forced on the dismissal and impeachment of Suffolk; was a member of the commission appointed in 1386 to reform the kingdom and the royal household; and took up arms when Richard began proceedings against the commissioners.
By refusing an invitation to dinner the duke frustrated the first attempt, but on the 11th of July 1397 he was arrested by the king himself at his residence, Pleshey castle in Essex.