In 1337 King Edward III upgraded the existing earldom of Cornwall and made it into a duchy. He also established the convention that it would henceforth belong to the eldest son of the monarch. The recipient in 1337 and first Duke of Cornwall was the seven-year old Edward of Woodstock.
On coming of age young Edward ensured that Duchy offices were packed with his own men. Very few Cornish in the years before the 1460s held Duchy posts. The Duke was keen to make more money from his estate. In addition, unlike the immediately preceding earls, he was also prepared to order action against local gentry who overstepped the mark and took the law too frequently into their own hands. He curbed local hard men such as John Trevarthian and Sir John l’Ercedekne, while imprisoning his own Duchy steward in Launceston Castle in 1357 for misdemeanours.
But despite this oversight, Edward remained an absentee lord, only visiting Cornwall twice, for a couple of weeks in 1354 and over Christmas and the New Year in 1362-63. Each time he ventured only as far west as Restormel. His main interest became squeezing the surplus from the Duchy to pay for the wars he was busy fighting in France.
At the age of 16 Edward had played a prominent part in the victory at Crecy. Later, in 1356, he captured the French King at Poitiers and took him back to England. Becoming Prince of Aquitaine in 1362 Edward never returned to Cornwall after his visit late that year. In his absence over the Channel, oversight inevitably became looser and even more remote. Cornishmen began to pick up more Duchy offices, while endemic lawlessness and family feuding returned.
Meanwhile, the Duke was getting involved in the Castilian civil war. More battles were won there until he contracted dysentery in 1367. Recurrent bouts of illness pursued him through his final decade and he eventually died of dysentery at Canterbury in 1376, aged 46.
And why was he ‘black’? This may be a later designation as the first reference did not appear until the 1530s. It’s been suggested that it came from the colour of his shield or armour. Others insist it stems from his brutal reputation in Aquitaine, where he was not slow to put the French to the sword. However he obtained his sobriquet, this martial Duke seems to have treated his Duchy as a convenient cash cow rather than any more meaningful constitutional possession.