Religions have come into being at all times and in all parts of the world. They are on one hand expressions of the human need for a higher power which gives meaning to origin and destiny. On the other hand, they reflect environmental conditions as well as the cultural and social achievements which have produced them. In general a religion formulates the canon of values of a specific community at a specific time.
Humans have migrated all times. Most of them have done it rather unwillingly, in order to avoid conflict with other groups, to react to changing environmental conditions or to find better ones, often simply because the group had become too large to survive in the ancestral area.
This caused reciprocal conflict, majority relationship changed and minorities in particular had a hard time; many fled because they wanted to practice their religions without fearing for their lives.
The migration movements are one of the two main reasons why religious encounter each other. Conversely, there were and are repeated attempts to set one’s own religion as a standard for the lives of the other. Generally, missionaries followed in the footsteps of conquerors – if they did not even go ahead of their forces. They were sent out to convince presumed unbelievers by means of more or less pressure that is was worth changing sides in order to achieve peace on earth or in heaven.
In the case of religions, mixing two ideas to create a new one meant the creation of a new religion out of equal or unequal parts of two old religions. The practice is certainly complex for it has always to do with the individual approach to the entrenched religion, with the adoption of elements of the new, and always with whether and how pressure is exerted for one’s own practice to be changed, and how flexible the encounter with this pressure can and should be.
Syncretism is a concept that can only be applied to a closed development. However, many people live in a religious in-between area. A flagrant example is given by various religious affiliations within very small units, as in West Africa, where the multiplicity of faith communities – Catholicism, Protestantism, Islam, Evangelicals, Jehova’s Witnesses, animism – cuts right to the extended families. When part of a family moves away from its ancestral home and converts to Roman Catholicism in the next town, another part reaches the cost, where the Evangelical church is particularly strong, and converts there, then nevertheless all the members meet from time to time at the place of origin to sacrifice to their ancestors or to a local deity, who must be appeased to provide the next good harvest. The monotheistic religions do not look at all favorably on this, for they quite clearly claim exclusive agency.
Finally the great world religions are also syncretistic models. Judaism, Christianity and Islam not only have the same origin, sharing the creation and genesis myth, but can also be seen in their origins as a reaction to external influences or their own distribution in new regions. Hinduism and Buddhism have during time adopted influences from other religions, Buddhism being explicitly open to enrichment by other spiritual ideas and models. At the same time, it is the only one of the great religions to demand what happens in any case – change.