After the fall of the Roman empire in the 5th century, scientific thinking about the causes of mental illness and depression again regressed. During the Middle Ages, religious beliefs, specifically Christianity, dominated popular European explanations of mental illness. Most people thought that mentally ill people were possessed by the devil, demons, or witches and were capable of infecting others with their madness. Treatments of choice included exorcisms, and other more barbaric strategies such as drowning and burning. A small minority of doctors continued to believe that mental illness was caused by imbalanced bodily humors, poor diet, and grief. Some depressed people were tied up or locked away in "lunatic asylums".