John of Gaunt indeed still retained influence over the king.

It was the support of the Duke of Lancaster after his return from his Spanish campaign which had enabled Richard to hold in check the Duke of Gloucester and the party that he led; and the anxiety of the young king to retain this support was seen in his grant of Aquitaine to his uncle, and in the legitimation of the Beauforts, John's children by a mistress, Catherine Swinford, whom he married after the death of his second wife.

The friendship of the Duke brought with it the adhesion of one even more important, his son Henry, the Earl of Derby.

As heir through his mother, Blanche of Lancaster, to the estates and influence of the Lancastrian house, Henry was the natural head of a constitutional opposition, and his weight was increased by a marriage with the heiress of the house of Bohun.

He had taken a prominent part in the overthrow of Suffolk and De Vere, and on the king's resumption of power he had prudently withdrawn from the realm on a vow of Crusade, had touched at Barbary, visited the Holy Sepulchre, and in 1390 sailed for Dantzig and taken part in a campaign against the heathen Prussians with the Teutonic Knights.