Chapter 5 on amendment, modification, and revision is organically linked with the former chapter on interpretation. It deals with the possibility of a temporal motion of a treaty through amendment, modification or revision. This may lead to either increase (auxesis), diminution (meiosis), or even alteration (alloiosis) of a treaty. The chapter goes through the development of the rules of amendment and modification in the VCLT, and also examines the contemporary development of the law of treaties through conferences of parties established by multilateral environmental agreements. This practice has led to new approaches to treaty modification, which did not exist in classical international law. It may be said that such modifications are effected through secondary legislation, which in turn may lead to the questions of legitimacy. This chapter concludes with an examination of the patterns of amendment and modification that emerge from the multilateral treaties that have been registered in the League of Nations and United Nations Treaty Series.