In the late 18th century, Manchester was much smaller than it is today with about 40,000 people living there. This changed at the start of the Industrial Revolution. During this time, there were revolts about the living conditions for workers. The most well known of these revolts was the Peterloo Massacre. Fifteen to twenty people were killed during the Peterloo Massacre and hundreds of other people were hurt. In 1780, Richard Arkwright built the first cotton mill in the area.