Commemorative plaques cast from brass are a characteristic art form of the Benin culture of West Africa  Some scholars, noting that the oldest surviving plaques date to the 1400s, hypothesize that brass-casting techniques were introduced by the Portuguese, who came to Benin in 1485 A  D  But Portuguese records of that expedition mention cast-brass jewelry sent to Benin' s king from neighboring Ife
So it is unlikely that Benin' s knowledge of brass casting derived from the Portuguese
In the 1400s the Portuguese did not use cast brass for commemorative plaques.