further dates were retrieved in the course of new archaeological excavations, extending the beginnings of the Nok tradition even further back in time. Because of the similarities between the two sites, archaeologist Graham Connah believes that "Nok artwork represents a style that was adopted by a range of iron-using farming societies of varying cultures, rather than being the diagnostic feature of a particular human group as has often been claimed." Benin art Benin art is the art from the Kingdom of Benin or Edo Empire (1440–1897), a pre-colonial African state located in what is now known as the South-South region of Nigeria. The Benin Bronzes are a group of more than a thousand metal plaques and sculptures that decorated the royal palace of the Kingdom of Benin in what is now modern-day Nigeria. Collectively, the objects form the best-known examples of Benin art, created from the thirteenth century onwards, by the Edo people, which also included other sculptures in brass or bronze, including some famous portrait heads and smaller pieces. In 1897 most of the plaques and other objects in the collection were taken by a British force during the Benin Expedition of 1897, which took place as British control in Southern Nigeria was being consolidated. Two hundred of the pieces were taken to the British Museum, while the rest were purchased by other museums in Europe. Today, a large number are held by the British Museum, as well as by other notable collections in German and American museums. Igbo The Igbo produce a wide variety of art including traditional figures, masks, artifacts and textiles, plus works in metals such as bronze. Artworks form the Igbo have been found from as early as the 9th century with the bronze artifacts found at Igbo Ukwu. Their masks are similar with the Fang ones, being white and black in about same parts. Yoruba Yoruba art is best known for the heads from Ife, made of ceramic, brass and other materials. Much of their art is associated with the royal courts. They also produced elaborate masks and doors, full of details and painted in bright colors, such as blue, yellow, red and white. Other ethnic groups of Nigeria Mali The primary ethnic groups in Mali are the Bambara (also known as Bamana) and the Dogon. Smaller ethnic groups consist of the Marka, and the Bozo fisherman of the Niger River. Ancient civilizations flourished