The naming of the new puppy, Edith says that they always name their dogs after something Egyptian. Robert points out that Tia'a was the mother of Thutmose IV and wife of Amenhotep II. She was, during the latter's time, a faceless concubine. Only after her son became Pharaoh was she given the title of wife to Amenhotep. All monuments depicting her we're created by her son.
The H. Rider Haggard referred to was the celebrated 19th Century British adventurer who wrote "She" and "King Solomon's Mines."
When naming the new puppy, Lord Grantham and Edith show a considerable knowledge on Ancient Egypt that was also depicted in s6e5. This may be a nod to the filming location of the series, Highclere Castle, as it not only houses a large Egyptian exhibition, which is opened to the public, but it is also owned by the Earls of Carnarvon. George Herbert, the 5th Earl of Carnarvon, became famous as the financial backer for the expedition that found the tomb of Tutankhamun.
The episode won an Emmy Award for Outstanding Production Design for a Narrative Period Program (One Hour or More).
When Robert says "curiouser and curiouser," the quote is from Lewis Carroll's "Alice in Wonderland."