Prior to the introduction of modern flush toilets, most human waste disposal took place outdoors in outhouses or latrines. However, the ancient cities of the Indus Valley Civilization, e.g., Harapp and Mohenjo-Daro, which are located in present day India and Pakistan, had flush toilets attached to a sophisticated sewage system and other forms of toilets were used both in the time of the Romans and Egyptians as well. In the Middle Ages wealthy people might use rags to wipe their behinds. Ordinary people often used a plant called common mullein or woolly mullein. Although a precursor to the modern flush toilet system was designed in 1596 by John Harington, the toilet did not enter into widespread use until the late nineteenth century, when it was adopted in English upper class residences.