Duban appears in The tale of the vizier and the Sage Duban and is a sage described as being a man of extraordinary talent. The ability to read Greek, Persian, Turkish, Arabic, Byzantine, Syriac and Hebrew, as well as a deep understanding of botany, philosophy and natural history are only a few.
He cures King Yunan from leprosy. Duban works his medicine in an unusual way: he creates a mallet and ball to match, filling the handle of the mallet with his medicine. When the king plays with the ball and mallet, he perspires, thus absorbing the medicine through the sweat from his hand into his bloodstream. After a short bath and a sleep, the King is cured, and rewards Duban with wealth and royal honor.
Yunan's vizier, however, becomes jealous of Duban, and persuades Yunan into believing that Duban will later produce a medicine to kill him. The king eventually decides to punish Duban for his alleged treachery, and summons him to be beheaded. After unsuccessfully pleading for his life, Duban offers one of his prized books to Yunan to impart the rest of his wisdom. Yunan agrees, and the next day, Duban is beheaded, and Yunan begins to open the book, finding that no printing exists on the paper. After paging through for a time, separating the stuck leaves each time by first wetting his finger in his mouth, he begins to feel ill. Yunan realises that the leaves of the book were poisoned, and as he dies, the king understands that this was his punishment for betraying the one that once saved his life.