Different Religions Members visiting together

The English word is first attested in the early 17th century, from Modern Latin syncretismus, drawing on Greek συγκρητισμός (synkretismos), supposedly meaning “Cretan federation”, but this is a spurious etymology from the naive idea in Plutarch’s 1st-century AD essay on “Fraternal Love (Peri Philadelphias)” in his collection Moralia (2.490b).