Last week, I started reading Chaucer's The Canterbury Tales. I just finished "The Knight's Tale" this morning. While the story is set in Ancient Greece and the characters often talk about the Greek gods, I found a lot of Christian imagery within the descriptions of those Greek gods.
The rest of this post contains spoilers.
Most of the tale focuses on two knights (Palamon and Arcite), who both want the same woman (Emily) to be their wife. The king (Emily's brother) eventually comes up with a challenge - each knight will return with one hundred knights and fight for her. The woman herself has no say in what happens. In Part III, three of the main characters each go off to a temple to pray to a particular god. Palamon goes to the Temple of Venus to ask for Emily as his wife, appealing to love; Emily goes to the Temple of Diana to ask to not be married to either, appealing to chastity; and Arcite goes to the Temple of Mars to ask for support in battle, appealing to the god of war's desire for victory.
While it's not exactly comparable, each character's going to a different god bears some resemblance to the Trinity. A better example is what Emily says to Diana - "O help me Goddess, for none other can, / By the three Forms that ever dwell in thee." My edition has a note for this line - "In Heaven, Luna. On earth, Diana. In Hell, Proserpina." In addition to the three-fold nature of Diana, there's also the three-fold nature of the Trinity. Admittedly, those are my weakest examples of the Christian imagery used to describe Greek gods.
After Venus indicates to Palamon that he will wed Emily and after Mars indicates to Arcite that he will win the battle, the pantheon discusses the contradictory nature of the two. Saturn tells Venus that he will work everything out and says "'Twas I slew Samson when he shook the pillar." The story of Samson is in the book of Judges in the Old Testament in the Bible. Here, a Greek god is given credit for a story related in the scripture of a different religion.
While Arcite does win the battle for Emily, shortly afterwards, he falls from his horse and suffers a head injury that eventually proves fatal. At his funeral, the king and the king's father bear cups "brimming with honey and milk, with blood and wine." In this one line, there are two Biblical allusions. The first - "honey and milk" - refers to the Promised Land that God gave to the Israelites. Exodus 3:7-8 - "Then the Lord said, 'I have surely seen the affliction of my people who are in Egypt and have heard their cry because of their taskmasters. I know their sufferings, and I have come down to deliver them out of the hand of the Egyptians and to bring them up out of that land to a good and broad land, a land flowing with milk and honey, to the place of the Canaanites, the Hittites, the Amorites, the Perizzites, the Hivites, and the Jebusites.'" The second - "blood and wine" - refers to the Last Supper and Communion. Matthew 26:27-28 - "And he took a cup, and when he had given thanks he gave it to them, saying, 'Drink of it, all of you, for this is my blood of the covenant, which is poured out for many for the forgiveness of sins.'" Additionally, of the two cups carried by the king and his father, one holds an allusion to the Old Testament, and one holds an allusion to the New Testament, which recalls the Law and the Gospel - an-other feature of Christianity.
Finally, in his eulogy at Arcite's funeral, the king reflects on transience, "'That same Prince and Mover then,' said he, / 'Stablished this wretched world, appointing ways, / Seasons, durations, certain length of days, / To all that is engendered here below.'" While it's later revealed that he's talking about Saturn, the language used to describe his establishment of the world is similar to that used to describe Creation in Genesis 1:14 - "And God said, 'Let there be lights in the expanse of the heavens to separate the day from the night. And let them be for signs and for seasons, and for days and years.'"
When I read parts of Edmund Spenser's The Faerie Queene in a class a few years ago, I noticed this same, seemingly-contradictory combination of allusions to classical mythology and Christian elements. I asked about this, and - from what I recall - the combination was an effort to synthesize something that held the religious beliefs of the day but that also hearkened back to the Greek writers. I think that's what Chaucer (or perhaps the titular Knight) is doing here.
And it's not just the religious elements. The Knight explains that this story takes place in Thebes and Athens - classical Greece - but he describes Palamon and Arcite as if they were modern knights. He has them wear armor, ride horses, and fight with long-swords. Like he does with the religious elements, he combines an ancient exterior with modern beliefs and practises.
According to the introduction in the edition I have, at that point in history, story telling wasn't so much about composition as it was about elaboration. Authors didn't write their own stories; they merely embellished previous stories. So I think Chaucer's amalgams are his ways of adapting older stories to a contemporary audience.