The period of the Rightly Guided Caliphate begins with the period immediately following the death of the Prophet and covers the reigns of those caliphs – namely, Abu Bakr, Umar, Uthman and Ali- who truly followed in the Prophet’s footsteps. In this article we attempted to find out the degree of relationship by consanguinity between these caliphs, supposing that such research would uncover the reasons and their importance which may lie behind their seizing of power. All being belong to the Quraish tribe, the first four caliph’s family lineage goes back to the same ancestor, namely Ka’b b. Luey. These people had naturally established new relationships between themselves and their children. We, in this article, defend the idea that their relationship had played no role in their succession to the throne. Being a relative of the Prophet was considered as important. However, such relationship can not only be understood in terms of genealogy, but it is a relationship that has wider meaning.