Syncretism () is the combining of different beliefs, while blending practices of various schools of thought. Syncretism involves the merging or assimilation of several originally discrete traditions, especially in the theology and mythology of religion, thus asserting an underlying unity and allowing for an inclusive approach to other faiths. Syncretism also occurs commonly in expressions of arts and culture, (known as eclecticism) as well as politics (syncretic politics). 

The English word is first attested in the early 17th century, from Modern Latin "syncretismus", drawing on Greek ("synkretismos"), meaning "Cretan federation". 

The Greek word occurs in Plutarch's (1st century AD) essay on "Fraternal Love" in his "Moralia" (2.490b). He cites the example of the Cretans, who compromised and reconciled their differences and came together in alliance when faced with external dangers. "And that is their so-called "Syncretism" [Union of Cretans]". 

Erasmus probably coined the modern usage of the Latin word in his "Adagia" ("Adages"), published in the winter of 1517–1518, to designate the coherence of dissenters in spite of their differences in theological opinions. In a letter to Melanchthon of April 22, 1519, Erasmus specifically adduced the Cretans of Plutarch as an example of his adage "Concord is a mighty rampart". 

Overt syncretism in folk belief may show cultural acceptance of an alien or previous tradition, but the "other" cult may survive or infiltrate without authorized "syncresis" nevertheless. For example, some Conversos developed a sort of cult for martyr-victims of the Spanish Inquisition, thus incorporating elements of Catholicism while resisting it.
In Greek, did it appear in an essay?
The Greek word occurs in Plutarch's (1st century AD) essay