We were talking about the origin of the pound of flesh, stanley2. I read more of the wikipedia article I cited earlier and apparently Shakespeare did not make it up: https://en.wikipedia.org/wiki/The_Merchant_of_Venice
The forfeit of a merchant's deadly bond after standing surety for a friend's loan was a common tale in England in the late 16th century. In addition, the test of the suitors at Belmont, the merchant's rescue from the "pound of flesh" penalty by his friend's new wife disguised as a lawyer, and her demand for the betrothal ring in payment are all elements present in the 14th-century tale Il Pecorone by Giovanni Fiorentino, which was published in Milan in 1558. Elements of the trial scene are also found in The Orator by Alexandre Sylvane, published in translation in 1596. The story of the three caskets can be found in "Gesta Romanorum", a collection of tales probably compiled at the end of the 13th century.