Celtic art is art associate with various people known as Celts; those who spoke the Celtic languages in Europe from pre-history through to the modern period, as well as the art of ancient people whose language is unknown, but where cultural and stylistic similarities suggest they are related to Celts. Also covered by the term is Celtic revival art from the 18th century to the modern era, which began as a conscious effort by Modern Celts to express self-identification and nationalism.