Signet ring of the Black Prince. In 1337, Edward, the Black Prince was created Duke of Cornwall, taking precedence over all earls. Dukedoms were reserved for members of the Royal Family until 1387, when Robert de Vere, 9th Earl of Oxford, the favourite of Richard II, was created Duke of Ireland for life. De Vere had previously been created Marquess of Dublin for life, making him the first person to hold a dignity of such a rank between Dukes and Earls.
The birth of Edward the Black Prince, eldest son of Edward III on this day 15th June, 1330. He married his cousin Joan, 'The Fair Maid of Kent' who gave him two sons, one of whom was the future Richard II