Justification Of Copyright
The first copyright act was passed in England in 1709, before this there was only the Register of the Stationers' company which ran the Stationers' guild. By this time the register was being ignored by every publishing business which was not a member of the guild and many members within the guild. This came about because the guild had lost it's monopoly powers in 1695 when the royal prerogative that required the guild to censor "seditious, heretical and blasphemous works" expired.
The new bill was drafted under the name "An Act for the Encouragement of Learning" and enacted in 1709 then came into force in 1710.
With this act a monopoly was given to the Author for the period of 14 years from the work being entered into the Stationers' register. A further 14 years would be granted if the author was still alive then the first period expired. The entry into the stationers register loan modification also required that nine copies of the publication be given to the state for distribution to the National libraries.
With the exception of these changes the Act was little different from the censorship laws that has previously existed, the shift of control from the Crown to the Author took many years to make itself obvious. As did the change from perpetual copyright to time limited.
The obvious aim of the Act was to stop a large number of "common law" (ie sue them!) court cases that were using very large amounts of court time.
The stated aims of the Act were to encourage learning and innovation by providing authors with an incentive to create new works and to ensure that those works are available to the public.
The requirement for nine copies and another requirement that "if anyone thought the published price of a book unreasonably high, the archbishop of Canterbury, or other authority, might, on appeal, fix a fair price." were direct additions for this.
An important point to note is that the aim to reduce the court cases between publishers makes this a commercial law, designed to stop big companies wasting court time over who has the better story.