Mahdism among the Islamic teachings is one of the issues that are discussed in many sources, at least more than 3000 volume is written about this case. Among all these categories “the sings of advent “is one of the most crucial issues in this field which is very important for Muslims. Of course this issue is not just related to Islamic sources, other religions believe in Savior too. In many Mahdism books the signs of advent have been divided to two categories: certain advent and uncertain advent. In some works which have been written during the past half century, some other categories such as geographic and chronological categories are presented. In this paper for the first time we try to collect different approaches in this issue and introduce them briefly. But any source or book which is used in this paper is introduced. This kind of categorization in this paper is used for the first time therefore there may be lack of clear and documented sources. In this article we have used qualitative research methods and Library research method so we have used most printed works in this field of study as well as Apocalypse encyclopedia. This paper can be suitable base for other researches and works in this case.
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