The Poor Man’s Guardian, one the first working class newspapers, was established by founding member of the London Working Men’s Society, Henry Hetherington. The newspaper – whose motto was 'knowledge is power' – was first published on 9 July 1831, and sold for one penny. This price ignored the fact there was a stamp duty of four pence payable per copy, but meant the poor were able to afford to read the news and politics of the day. Publishing without paying the stamp duty was a serious offence and Hetherington was imprisoned from September 1831 to March 1832, again for six months in 1833 and then for another two months in 1836. The paper ran until 1835 and was edited for the majority of this period by the intellectual Chartist Bronterre O’Brien. O’Brien also worked for other radical newspapers such as The True Sun, The Destructive, and Poor Man’s Conservative, The Twopenny Dispatch and The London Mercury, and later published his own newspaper entitled Bronterre’s National Reformer.