The advertising of patent medicines began at the same time as the creation of the public sphere, in which newspapers first became available and read in the new phenomena of coffee houses. In fact the early marketing of early medicines through their ‘letters patent’ (royal approval) fueled the circulation of early papers. Many advertising and sales techniques were pioneered by patent medicine promoters. To keep patent medicines in the early public sphere, they began to use distinctive bottle shapes, and by the mid 19th century this trend had continued with the use of skulls to denote that the contents contained poisons. Not only a clear visual reference, but also the distinctive shape would also be easily identifiable in the dim houses where candlelight often failed to penetrate the gloom of industrialized cities.