DOM GIANNI, AT THE INSTANCE OF HIS GOSSIP PIETRO, PERFORMETH
A CONJURATION FOR THE PURPOSE OF CAUSING THE LATTER'S WIFE
TO BECOME A MARE; BUT, WHENAS HE COMETH TO PUT ON THE TAIL,
PIETRO MARRETH THE WHOLE CONJURATION, SAYING THAT HE WILL
NOT HAVE A TAIL

The queen's story made the young men laugh and gave rise to some
murmurs on the part of the ladies; then, as soon as the latter were
quiet, Dioneo began to speak thus, "Sprightly ladies, a black crow
amongst a multitude of white doves addeth more beauty than would a
snow-white swan, and in like manner among many sages one less wise is
not only an augmentation of splendour and goodliness to their
maturity, but eke a source of diversion and solace. Wherefore, you
ladies being all exceeding discreet and modest, I, who savour somewhat
of the scatterbrain, should be dearer to you, causing, as I do, your
worth to shine the brightlier for my default, than if with my greater
merit I made this of yours wax dimmer; and consequently, I should have
larger license to show you myself such as I am and should more
patiently be suffered of you, in saying that which I shall say, than
if I were wiser. I will, therefore, tell you a story not overlong,
whereby you may apprehend how diligently it behoveth to observe the
conditions imposed by those who do aught by means of enchantment and
how slight a default thereof sufficeth to mar everything done by the
magician.

A year or two agone there was at Barletta a priest called Dom Gianni
di Barolo, who, for that he had but a poor cure, took to eking out his
livelihood by hawking merchandise hither and thither about the fairs
of Apulia with a mare of his and buying and selling. In the course of
his travels he contracted a strait friendship with one who styled
himself Pietro da Tresanti and plied the same trade with the aid of an
ass he had. In token of friendship and affection, he called him still
Gossip Pietro, after the Apulian fashion, and whenassoever he visited
Barletta, he carried him to his parsonage and there lodged him with
himself and entertained him to the best of his power. Gossip Pietro,
on his part, albeit he was very poor and had but a sorry little house
at Tresanti, scarce sufficing for himself and a young and buxom wife
he had and his ass, as often as Dom Gianni came to Tresanti, carried
him home with him and entertained him as best he might, in requital of
the hospitality received from him at Barletta