The British periodical press developed slowly and faltered under early official controls, but flourished when political conflict created opportunities for journalists and publishers. Political journalism rose and fell depending upon events, governmental policies, and publishers' courage; nonpolitical informative or ‘practical’ periodicals, on the other hand, gradually became a large and stable component of the press. From negligible beginnings, by 1695 hundreds of periodicals, with tens of thousands of issues and covering a wide range of subjects, had been published in Britain (see figure 25.1). No periodicals – defined loosely as numbered and/or dated series of pamphlets or sheets with uniform title and format – were published before 1620. (A possible exception was the weekly London bill of mortality, compiled by the parish clerks and printed as early as 1603–4, but it may have been published only in times of plague.) Several factors deterred the early appearance of periodicals. Most simply, someone had to conceive of them, and the idea was not obvious. For early publishers, prayer books, sermons, treatises and ballads were known texts for a known market; periodical publications, in contrast, require planning without knowing the text in advance. The concept, therefore, involved a leap of faith, as well as the financial risks of establishing networks of sources and distribution and an ongoing printing operation – an expensive undertaking for an untested market. The major barrier, however, seems to have been the hazardous implications of the subject for which the periodical was ideally suited – the news. [ABSTRACT FROM AUTHOR]