This meaning is also found in the name of the French language ("langue française"), whose literal meaning is "language of Île-de-France". It is not until the 19th and 20th centuries that the language of Île-de-France indeed became the language of the whole country France. In modern French, the French language is called "le français", while the old language of Île-de-France is called by the name applied to it according to a 19th-century theory on the origin of the French language – "le francien".