Substance and relation are the two primordial modes of being especially the human person. But the ancient and mediaeval philosophers emphasized only the substance as the primordial mode of the human person and regarded relation as an accident. Starting in the late mediaeval era, thinkers began to distrust the mode of substance and there came the quest for a new mode of being. During the late modern era and the early contemporary period many philosophers laid emphasis no more on substance but on relation. But today some scholars, like W. Norris Clarke, are trying to formulate a notion of ontological substance and relation as two equally primordial modes of being rather than emphasizing one over the other. I wish to emphasize that today being or person is no longer conceived only as substance or only as relation but as substance and relation which are equal primordial modes of being. This research begins by analysing substance in the history of philosophy, and then relation. After which it tries to unify both, leading to an attempt at the development of the notion of the human person as relational-substance.