This man, Mansa Musa, flooded Cairo with his generosity. He left no court emir nor holder of a royal office without the gift of a load of gold. The people of Cairo made incalculable profits out of him and his travelling party in buying and selling and giving and taking. They exchanged gold until they depressed its value in Egypt and caused its price to fall. According to this account, what was the effect of Musa’s visit to Cairo?