After group members witnessed the Peterloo Massacre in 1819 , and the closure of the liberal '' Manchester Observer '' by successive police prosecutions , it decided the time was right to advance its liberalist agenda . In 1820 , Brotherton , Shuttleworth and Thomas Potter founded the Manchester Chamber of Commerce . In the following year , the group supported John Edward Taylor found the liberal newspaper the '' Manchester Guardian '' to which they all contributed . Published by law only once a week , Taylor continued to edit the newspaper until his death
Peterloo Massacre
Peterloo Massacre
Thomas Potter (mayor)