The aim of this paper is to compare the concept of theophany (i.e. the divine manifestation) at Maximus the Confessor and Johannes Scotus Eriugena. Maximus, in Ambigua ad Johannem, and Eriugena, in Periphyseon, show that God reveals Himself in both invisible and visible realities of the universe (which have their cause and purpose in Him) and allows them to participate in Him, during the ascendant process of reversion towards the divine unifying simplicity. In developing their doctrines, both authors point out two major stages: the descendant of Godhead towards human beings (I will refer here only to them, although it is known that angels are also receivers of the divine manifestation) and the ascension of human beings towards God. This bivalent process depends on a sum of moral and intellectual conditions that human beings need to accomplish in order to be able to contemplate God throughout the creation. Here comes out one of the main differences between Maximus and Eriugena: while the former emphasizes the practical life and the struggle against sins as a starting point towards gaining knowledge, hence the possibility of seeing God in creation, the latter seems to pass cursory over the purgatio, and to treat quite straightly the illuminatio and the deificatio. An explanation for the Eriugenian highlight on the intellectual struggle instead of the ascetic one (more specific to Maximus) must come from the different monastic traditions (Western comparing to Eastern) and from the historical context in which the two authors wrote their works.