Why arguments have broken out about the Benin Bronzes

Whether or not the British Museum should return its Benin Bronzes has caused lots of arguments. Nigeria argues that they should be returned because they were originally taken from Benin City without permission. Some museums have returned looted Edo artwork to Nigeria, but British law prevents the British Museum from doing so. In the USA, descendants of West African enslaved people are trying to stop the return of Edo artwork to Nigeria. This is because some of the art was made using metals that were traded by Europeans for enslaved people.