What was the main commodity traded in the trans-Saharan trade during the middle ages?

Salt and gold

Who was chained to a rock as a sacrifice to a sea monster before Perseus rescued her? What movie depicting Mafia family life starred Marlon Brando? What kind of mammal was once mistakenly classified as a rodent due to its teeth? Who becomes Venom after Eddie Brock? Who developed the psychoanalytic theory of human personality?