Final answer:
In Humoral Theory, a melancholic temperament is attributed to an excess of black bile, based on the teachings of Hippocrates and Galen.
Step-by-step explanation:
According to Humoral Theory, a person who displays a melancholic temperament was believed to have an excess of black bile. This concept dates back to ancient times, starting with Hippocrates, who associated personality traits with four bodily fluids, or humors. These included yellow bile (choleric), black bile (melancholic), red blood (sanguine), and white phlegm (phlegmatic). Galen further developed this theory, indicating that a melancholic person might appear reserved, anxious, and unhappy due to an imbalance of the humors.