The names Parmigiano Reggiano and Parmesan are protected designations of origin (PDO) for cheeses produced in these provinces under Italian and European law.

However, approximately 90% of cheeses marketed under the Parmigiano Reggiano name in the United States are produced domestically, rather than in the PDO-designated regions of Italy.

[14] Slivers and chunks of the hardest parts of the crust (also called the rind) are sometimes simmered in soups, broths, and sauces to add flavor.

[15] According to legend, Parmigiano Reggiano was created in the course of the Middle Ages in the comune (municipality) of Bibbiano, in the province of Reggio Emilia.

Historical documents show that in the 13th and 14th centuries, Parmigiano was already very similar to that produced today, which suggests its origins can be traced to far earlier.

[8] It was praised as early as 1348 in the writings of Boccaccio; in the Decameron, he invents a 'mountain, all of grated Parmesan cheese', on which 'dwell folk that do nought else but make macaroni and ravioli, and boil them in capon's broth, and then throw them down to be scrambled for; and hard by flows a rivulet of Vernaccia, the best that ever was drunk, and never a drop of water therein'.

[16] During the Great Fire of London of 1666, Samuel Pepys buried his "Parmazan cheese, as well as his wine and some other things" to preserve them.

[17] In the memoirs of Giacomo Casanova,[18] he remarked that the name Parmesan was a misnomer common throughout an "ungrateful" Europe in his time (mid-18th century), as the cheese was produced in the comune (municipality) of Lodi, in Lombardy, not Parma.

[19] Between November 2013 and January 2015, an organised crime gang stole 2039 wheels of Parmigiano Reggiano from warehouses in northern and central Italy.

The devastation was profound, displacing tens of thousands of residents, collapsing factories, and damaging historical churches, bell towers, and other landmarks.

In order to assist the cheese producers, Modena native chef Massimo Bottura created the recipe riso cacio e pepe.

[citation needed] The name is legally protected in the European Union and, in Italy, exclusive control is exercised over the cheese's production and sale by The Consortium of Parmigiano Reggiano, which was created by a governmental decree.

[2] Within the European Union, the term Parmesan may only be used, by law, to refer to Parmigiano Reggiano itself, which must be made in a restricted geographic area, using stringently defined methods.

In many areas outside Europe the name Parmesan has become genericised and may denote any of a number of hard Italian-style grating cheeses.

[34][35] These cheeses, chiefly from the US and Argentina, are often commercialised under names intended to evoke the original, such as Parmesan, Parmigiana, Parmesana, Parmabon, Real Parma, Parmezan, or Parmezano.

[2] After the European ruling that "parmesan" could not be used as a generic name, Kraft renamed its grated cheese "Pamesello" in Europe.

In the United States, the Code of Federal Regulations includes a Standard of Identity for "Parmesan and Reggiano cheese".

[41][42][43] Several American manufacturers have been investigated for allegedly going beyond the 4% cellulose limit (allowed as an anticaking agent for grated cheese, 21 CFR 133.146).

Developed by Italian Argentine cheesemakers, the cheese is made in smaller wheels and aged for less time, but is otherwise broadly similar.