One very important factor, overlooked by modern studies, considered to be taken directly from Orpheus and the "Orphic communities" is that of monotheistic religion. Orpheus himself is taken to be prophet of a particular type of mystery-religion, as W.K.C. Guthrie, in whose book Orpheus and the Greek Religions most of the present information can be found, points out, the "mysteries of Dionysos". Indeed the pagan mysteries of Dionysos are said to have influenced Christianity a great deal. Guthrie speculates on the notion that since Dionysos (son of Zeus, of whose leg Dionysos’ heart is implanted within) has many roles, and different names for his identification, study on this period has pointed to polytheism (more than one God) when in fact Phanes and Hades (the place, also named, that Orpheus descended and returned) etc. were used to identify Dionysos' various functions. This and many other factors, supposes Guthrie, were what helped prepare the Graeco-Roman world for Christianity. Here we will discuss those other factors.
In an Orphic community (one in which treated Orpheus' writings as a holy scripture, and at least followed Plato's suspicion that Orpheus' writings were too strong to be mere poetry) religious texts and acts were presided over by Telete, daughter of Dionysos. Some in that community thought it acceptable to ignore the "Orphic life" (some basic necessities that ought to be adhered in order to fulfill Orpheus' prophecies, of which more in a moment) and simply assume that teletai alone would secure their salvation, of which the name for this calling was Orpheotelestai (Orpheus-initiators). But this, according to scholarly analysis, is based on a textual misunderstanding (and sounds rather like an ancient form of Pascal's Wager in that one ought to act like one believes – just incase – and, not necessarily specified by Pascal, enjoy all the [Dionysian?] fun rather than commit to the "rules," in order to achieve salvation). Plato, Theophrastas, and Plutarch all condemned the Orpheotelestai for, among other things, guaranteeing that no shared belief was practiced between the Orphics on account of their misunderstandings. The Orphic scriptures did, actually, demand a number of religious formalities, namely conversion, adherence to a religious way of life, original sin, communion, and a particular eschatology (final rewards of the pure Orphics was the eternal enjoyment of union with God). These said notions have, undeniably, a lot in common with Christianity, says Guthrie, and inform part of Christianity's own identity.
Later on in the Greek world St Paul's "Hellenism" advanced his popularity (the Gospel of Luke explains that the name Paul to identify St Paul was first used in the Graeco-Roman world, rather than using his real name Saul. Paulus was a Roman surname and St Paul was the first to use it specifically as a first name, using it when engaging in his ministerial role to Gentiles), as well as sharing a common tongue (which Paul dedicated a lot of time perfecting). According to Guthrie, other than avoiding talk of the (Dionysos) mysteries, Paul's triumph in the Graeco-Roman world was guaranteed by the great similarities in Christianity and Orphism.
A further comparison should be found in the effect each religion has had on man, in the sense of how man has transformed into individual. Guthrie has described Orphism as "the beginning of man as an individual" since Orphism promoted the individual soul in order to curb the age of competing interests driving it "from the minds of all but the few." The notion that separation brought people together was later used as the founding concept of Christian love, or agape (expression of love in God). In fact, it was rather ambiguously accounted for in the notoriously misunderstood chapters John 15:6 and Matthew 10:34 “Think that I come to send peace on earth: I came not to send peace, but a sword”. As it was rightly elucidated by G.K. Chesterton in his Orthodoxy, Christianity is "on the side of humanity and liberty and love" as well as, and not hypocritically, "a sword which separates and sets free ... that any man who preaches real love is bound to beget hate. It is as true of democratic fraternity as a divine love." The Christian pursuit, in other words, needs to know its enemy in order to realise the agape revolution (in his Sermon on the Mount, Jesus tells his audience that they must not hate their enemy, but love him in order that they, too, can one day be part of the expression of love. What is crucial here is that the enemy be identified, realised). This separation of souls, of individuality, as such, is the only transformation obtainable to promote both freedom and union, and who could deny that this explicitly Christian assertion has an Orphic root.
What critics may object to in Guthrie's work is that for all his historical work, whether Orphic religion had any real - other than purely analogous - influence on Christianity is all speculation. And this speculation does premise itself on rather grand questions concerning monotheism, its roots and its theological implications. For me, it does offer cultural reasons as to why the Graeco-Roman world took to Paul's Christianity, but it doesn't show Christianity to be in direct correlation to the poetry of Orpheus. The main point, whether Orphism marked the beginning of monotheism is a harder question to resolve. It certainly contradicts Freud's research on the beginnings of monotheism, designating Moses who popularised and intellectualised monotheism in order for the Hebrews to worship one God, rather than embracing the Sun-God Aten (and was subsequently killed by the Jews, who later regretted their decision to kill Moses and acknowledged him in their religion, guaranteeing guilt as part of the Jewish faith). As such, Freud considered the Jewish God at the beginning of monotheism. What is difficult to discern in Guthrie's text is at what point in history began the confusion of whether Dionysos was one God with many functions, or one of many functioning Gods. It is certainly a more established view that acknowledged Greek Gods in their plenty, and it is a problem not having any conclusive reasons as to why Greek and Thracian (group of Indo-European tribes) societies might have found it necessary to acknowledge Dionysos as monotheistic (like Moses’ society did). But some pretty strong conclusions are drawn by Guthrie and others (like Robert Parker in his essay “Early Orphism”). It’s the view of scholar Jan Assman that Orpheus, like Moses, played the mediator of monotheism to a series of religious rites, not least of which in his poetry, and so the debate on the origins of monotheism remain.