Game of Thrones

The phrase "valar morghulis", the title for this episode, is High Valyrian meaning "all men must die". It is a traditional greeting in certain parts of Essos. "Valar dohaeris" (which is the title of the next episode, the season 3 premiere), meaning "all men must serve", is the traditional response to it. Along with Dothraki and Skroth, High Valyrian is one of the fictional languages created for the show by David J. Peterson based on what George R.R. Martin envisioned for his "A Song of Ice and Fire" novels which "Game of Thrones" is an adaptation of.

The title of this episode "The Old Gods and the New" refers to the two main religions in Westeros. The Old Gods are worshiped in the North and the Faith of the Seven, also known as the New Gods, elsewhere in Westeros (except for the Iron Islands which has its own religion, the Drowned God). There are occasions where people swear oaths by "the Old Gods and the New" as well.

In the opening credits, Jack Gleeson, who plays Joffrey Baratheon, mistakenly has the Stark direwolf sigil next to his name.

The title of this episode is a direct quote from the books. Arya Stark refers to herself as "The Ghost of Harrenhal" in "A Clash of Kings", Chapter 30.

The title of this episode, "What Is Dead May Never Die", is quoted from the Iron Islander's religious worship of the Drowned God. The Iron Islanders, called Ironborn, often use it as a war cry, or even as a formal greeting.

In the opening credit sequence a new destination visited in this episode, Dragonstone, "rises" from the map. Vaes Dothrak and the Wall also rise although they are not visited in this episode, but there is activity by key characters in their general areas of the world.