Syncretism

Combination of distinct beliefs or schools of thought

Syncretism is the combining or merging of various distinct beliefs or schools of thought, particularly religious ones. For instance, features and components of one religion are incorporated and absorbed into another. It can include assimilation of several originally discrete traditions, especially in theology and mythology, thus asserting an underlying unity and allowing for an inclusive approach to multiple faiths.

From Wikipedia, under CC BY-SA. More on occurri.