Sabrina Bartlett as Princess Isabella, Julian Ovenden as De Nogaret
De Nogaret (Julian Ovenden) appears to team up with Rodrigo of Catalonia (Enrique Arce) to stop the wedding between Princess Isabella (Sabrina Bartlett) and Prince Lluis (Marcos Franz) in the trailer for Season 1, episode 4 of History’s “Knightfall.” History/Larry Horricks

The upcoming wedding between Princess Isabella of France and Prince Lluis of Catalonia might not happen at all.

The synopsis for Season 1, episode 4 of History’s “Knightfall” reveals that Princess Isabella (Sabrina Bartlett) is betrayed. While the logline for the hour doesn’t name who the betrayer is, the trailer for the episode suggests that it’s none other than De Nogaret (Julian Ovenden).

In Season 1, episode 2, De Nogaret — the right-hand man to King Philip (Ed Stoppard) of France — told Princess Isabella that he doesn’t care who she marries. But whoever the lucky man is, De Nogaret said that he’ll see to it that she’s “one of Europe’s most powerful queens.” But in the trailer for the next episode, De Nogaret reveals that he’s still against Princess Isabella’s wedding to Prince Lluis (Marcos Franz) even after the latter decided to support France in a potential war against England.

When Rodrigo of Catalonia (Enrique Arce) admits that he regrets everything about the potential marriage between Prince Isabella and Prince Lluis, De Nogaret says they should stop it. “There is something you may wish to whisper to your Queen,” De Nogaret tells Rodrigo. While De Nogaret’s secret message to the Queen of Catalonia remains unclear, it’s expected that this would make the Queen change her mind about allowing her son marry Princess Isabella.

The trailer also teases the arrival of Queen of Catalonia in France, and it’s clear that the Catalan queen is not fond of Queen Joan of France (Olivia Ross). “So beautiful,” the Queen of Catalonia tells Queen Joan of Princess Isabella. “Let us [just] hope she is fertile as you.”

“I’m afraid his mother is a viper,” Queen Joan comments about the visiting queen.

Elsewhere in episode 4, a pagan helps Landry (Tom Cullen) search his past. In the trailer, Landry enlists the help of a pagan after seeing a familiar symbol that could lead him to the location of the Holy Grail. After the pagan put a drop of liquid into Landry’s eyes, the Master of the Templars sees some moments from his past, including his young self running through the wood while carrying a mysterious chest.

Also in this week’s episode, Gawain (Pádraic Delaney) investigates the murder of one of the men who broke into Godfrey’s (Sam Hazeldine) home last episode.

“Knightfall” Season 1, episode 4, titled “He Who Discovers His Own Self, Discovers God,” airs on Wednesday, Dec. 27 at 10 p.m. EST on History. Watch the trailer below: