The sculpture of a head, which probably represents a king of ife (4.9.6), was made using which medium?

The Bronze Head from Ife, or Ife Head, is an identity of eighteen copper alloy sculptures that were discovered in 1938 at Ife in Nigeria, the holy and ancient high capital of the Yoruba men. It is considered to serve a king. It was apparently made in the thirteenth-fourteenth era before any European connection had grasped position with the local people. The authenticity and modern craftsmanship of the things questioned Western understandings of African creativity at the time. A year after its conclusion, the Ife Head was shifted to the British Museum.