In short, copyright is a form of intellectual protection for original works of a creator, whether published or unpublished, giving them exclusive rights for its use and distribution.
The Copyright Law originated in 1710, as laid down in the "Statute of Anne" in Great Britain (Copyright Act 1709 8 Anne c.19). It was enacted in 1709, but didn't come into force until April 10, 1710. Through this act the author's rights became protected.
At the time of the Statute of Anne, copyright lasted for only fourteen years, but nowadays the duration of copyright protection is fifty to hundred years after the death of the author. The act came into existence because publishers profited from printing copies of the work without remunerating the author. The act was established "for the encouragement of learned men to compose and write useful books". The Statute of Anne allowed authors to earn a living from their work. The act formed the beginning of copyright protection, of Copyright Law.
Copyright applies to creative, artistic, intellectual, or scientific works. Following is a list of works to which copyright applies:
Ideas aren't covered by the Copyright Law. These would come under the category of "patents". Likewise, names and titles fall into the category of "trade marks". Also, you can't copyright derivatives of an existing work, because the work has to be original. For instance if you make a new arrangement, or a new orchestration to an existing melody, then the author of the original melody is still the copyright holder.