The Principality of Catalonia is a historic territory in the northeastern Iberian Peninsula, mostly in Spain and with an adjoining portion in southern France.The first reference to Catalonia and the Catalans appears in the Liber maiolichinus de gestis Pisanorum illustribus, a Pisan chronicle (written between 1117 and 1125) of the conquest of Minorca by a joint force of Italians, Catalans, and Occitans.

At the time, Catalonia did not yet exist as a political entity, though the use of this term seems to acknowledge Catalonia as a cultural or geographical entity.The counties that willd eventually make up the Principality of Catalonia are gradually unified under the rule of the Count of Barcelona.

In 1137, the County of Barcelona is unified dynastically to the Crown of Aragon, but Aragon and the Catalan Counties retain their own political structure and legal traditions.

Because of these legal differences and their use of different language—Aragonese and Catalan—an official recognition of the Catalan Counties as a distinct political entity becomes necessary.Under Alfons the Troubador, Catalonia was first used legally.Still, the term Principality of Catalonia is not used legally until the 14th century, when it is applied to the territories ruled by the Court of Catalonia.The term "Principality of Catalonia" remains in use until the Second Spanish Republic, when its use declines because of its historical relation to the monarchy.

Today, the term is used primarily by Catalan nationalists and independentists to refer collectively to the French and Spanish-administered parts of Catalonia.