As usual, my memory for dates is a bit vague ... resulting in a simplistic and slightly inaccurate post. Here's the info. re; the Stationer's Company (compressed from various sources).

In 1534, Henry VIII granted letters patent to the Chancellor of the University of Cambridge to appoint three printers who, within the University, could print and publish any books of which the Chancellor and three doctors approved. This is a very early example of a licence being granted to one or more persons to determine whether works were fit to print and, further, to be able to print them. After some time the King realised that there was the possibility of making money out of the printing process if an appropriate monopoly was put in place. Thus, in 1547 Edward VI granted a monopoly to the King's printer over a number of specific categories of material. The monopoly was granted over Acts of Parliament, books of the rights and services of the resettled Church of England, Bibles and testaments, law books and year books, almanacks, educational works and Latin grammars. This monopoly in favour of the King himself was, some years later, followed by what we might call an industry self regulation scheme if it was established today.

In 1557 the Stationer's Company was established by royal charter (it had originally been a book trade guild formed in 1403 by the association of scriveners, limners, bookbinders and stationers), and this charter was confirmed in the first year of Elizabeth's reign (1558). In 1566 an ordinance was passed by the Star Chamber for the censorship of the press. The effect of the Stationer's Company charter and the ordinance of the Star Chamber was that the Stationer's Company was given a monopoly over printing and broad powers to enforce it. For example, the ordinance of the Star Chamber prohibited any person from printing any book against the force and meaning of any ordinance, law, injunction or letters patent and the Stationer's Company was authorised to enter onto premises and inspect a printer's printing operations to ensure compliance with these regulations as well as to act as customs officials to intercept trade in books.

This is quite important because The Stationers Company register is often the source of earliest dates for many songs and, later, becomes useful for establishing first printings.

As a note of caution, though, it's worth reading this thread about song forgeries.

:-)
Ian