1852 - first mill opened for the manufacture of sheep dip in Berkhamsted by William Cooper, developed own printing works and produced labels that could not be easily imitated; 1868 - nephew William Farmer Cooper joined the company: William Cooper & Nephews; 1885 William Cooper dies; 1880s - new factory built; 1880 two other nephews Henry Herbert Cooper and Richard Powell Cooper joined the family business; 1891 - Richard Powell Cooper becomes sole owner of the company; 1913 - company overtaken by Richard Ashmole Cooper, Richard Powell Cooper's son; 1925 - company amalgamated with McDougall and Roberston Limited, chairman, Isaac McDougall; 1950s- production in Berkhamsted stops; 1959 - company acquired by the Wellcome Foundation Limited; later became Coopers Animal Health Limited; 1992 - Wellcome Foundation sold its environmental health business to French company Roussel Uclaf; 1995 -amalgamated into AgrEvo; 1997 - site closed.