The studies of mythologies prior to the 1760s were not a body of sacred stories but the science of allegorical reading.
Ancient Greeks were the first to question the history and meaning of myths. In the sixth century BC, Xenophanes of Colophon (570-478 BC) concluded that humans pictured their gods in human form as a type of self-flattery. Later, the interpretation of myth was largely influenced by Euhemerus, a Greek writer from about 300 BC. Euhemerism argues that certain gods were originally people and were venerated because of their contributions to the betterment of humankind. Early Christianity adopted a form of modified Euhemerism, which allowed Christians to explain classical Greek and Roman mythologies as comprised of mortal men, not divine beings. This also allowed the incorporation of Pagan gods into Christianity, which were believed to be distorted biblical stories.
The Ancient Greek scholar Plutarch (45-125 AD) argued that myths should not be accepted as literal, but searched for their hidden meaning and symbolic content. This allegorical-symbolic approach to myth continued through the Renaissance into the nineteenth century. During the Renaissance, the Catholic Church allowed classic Greek and Roman myths to be interpreted as moral allegories.
In the eighteenth century, intellectuals interpreted Biblical and Pagan myths as irrational and superstitious. Francis Bacon (1561-1626) in his Essays of Counsels (1691) continued the allegorical-symbolic approach in analyzing myths for their hidden meanings and concealed information.
Bacon (1691) Essays of Counsels.