It befell when King Arthur had wedded Queen Guinevere and fulfilled the Round Table, and so after his marvellous knights and he had vanquished the most part of his enemies–
. . . then so it befell that the Emperor of Rome, Lucius, sent unto Arthur messengers commanding him for to pay his truage that his ancestors have paid before him.

When King Arthur wist what they meant, he looked up with his grey eyes, and angered at the messengers passing sore.

–from Le Morte Darthur, by Thomas Malory.
Helen Cooper, ed. Oxford University Press, 1988.

13th century Round Table, at Winchester