Betrothed when a child to Elizabeth (d. 1363), daughter and heiress of William de Burgh, 3rd Earl of Ulster (d. 1332), he was married to her in 1352, but before this date he had entered into possession of her great Irish inheritance. He was called Earl of Ulster from 1347.
Having been named as his father's representative in England in 1345 and again in 1346, Lionel joined an expedition into France in 1355, but his chief energies were reserved for the affairs of Ireland.
Appointed governor of that country, he landed at Dublin in 1361, and in November of the following year was created Duke of Clarence, while his father made an abortive attempt to secure for him the crown of Scotland. His efforts to secure an effective authority over his Irish lands were only moderately successful; and after holding a parliament at Kilkenny, which passed the celebrated Statute of Kilkenny in 1367, he dropped the task in disgust and returned to England.
Lionel's wife died in Dublin in 1363, having given birth to a daughter, Philippa, whose descendants would one day claim the throne for the House of York. A second marriage was arranged for Lionel with Yolande or Violante, daughter of Galeazzo Visconti, lord of Pavia (d. 1378); the enormous dowry which Galeazzo promised with his daughter being exaggerated by the rumour of the time. Journeying to fetch his bride, Lionel was received in great state both in France and Italy, and was married to Violante at Milan in June 1368. Some months were then spent in festivities, during which Lionel was taken ill at Alba, where he died.
His only child, Philippa, married in 1368 Edmund Mortimer, 3rd Earl of March (1351-1381), and through this union Clarence became the ancestor of Edward IV. The poet Chaucer was at one time a page in Lionel's household.
Antwerp, famous in the middle ages and at the present time for its commercial enterprise, enjoyed in the 17th century a celebrity not less distinct or glorious in art for its school of painting, which included Rubens, Van Dyck, Jordaens, the two Teniers and many others.
In the 4th century Antwerp is mentioned as one of the places in the second Germany, and in the 11th century Godfrey of Bouillon was for some years best known as marquis of Antwerp.
Antwerp had reached the lowest point of its fortunes in 1800, and its population had sunk under 40,000, when Napoleon, realizing its strategical importance, assigned two millions for the construction of two docks and a mole.
Antwerp was the headquarters of Edward III during his early negotiations with Jacob van Artevelde, and his son Lionel, the earl of Cambridge, was born there in 1338.
Antwerp was not a "free" city though, since it had been reabsorbed into the duchy of Brabant in 1406 and was controlled from Brussels.
Antwerp experienced three booms during its century, the first based on the pepper market, a second launched by American silver coming from Seville (ending with the bankruptcy of Spain in 1557), and a third boom, after the stabilising Treaty of Cateau-Cambresis, in 1559, based on the textiles industry.