While the copyright law contains parody as one of the forms of legal licences, the problem at hand is to define what parody is. The parody as such is a derivative work derived from another copyright. To create parody involves, in legal terms, the use of the original copyright. Due to the legal licence, this can be performed without consent of the author of the original piece of work, but it remains necessary to observe general terms and conditions concerning the use of copyright and which are required in connection with the legal licences. One of the conditions is the use of the copyright in the scope that is limited to what is necessary. U.S. law practice, with a number of cases having been dealt with, shows that limitation of such scope brings up a number of issues. Historically, we can see that an author of parody can use gradually larger and larger parts from the parodied work.