- Isobel: "Oh, just one more thing. The dog. What should we do to stop Isis getting into the patients' rooms?"
- Robert: "I can answer that. Absolutely nothing."
- — Episode 2.03
Aside from a couple of episodes, one of the dogs is shown at the very beginning of the show's introduction, walking beside the Earl of Grantham.
Series One: 1912-1914 Edit
Pharaoh occasionally appears in the background in series one. The dog is never identified by name in the first season. Sometime between the end of series one (August, 1914) and the start of series two (July 1916), Pharaoh dies and is replaced by Isis.
- Carson: "It's a hard decision, Your Lordship, a very hard decision, but the honour of Downton is at stake."
- Robert: "Don't worry, Carson, I know all about hard decisions when it comes to the honour of Downton. Don't I boy?"
- — Episode 1.01
At some point In the gap between Series One and Series Two, Pharaoh dies and is replaced by Isis, another yellow labrador retriever. It is unclear how Pharaoh met his end, or whether or not Isis is related to him, but by 1916 she is an established part of the household.
Series Two: 1916-1919 Edit
Isis appears in Series Two when Mrs. Patmore feeds her leftover Crêpe Suzette after telling Ethel that none were left over from the previous night's dinner. She also made several background appearances.
Isobel also mentions her when she talks about the convalescent home, she asks what can be done about keeping her out of the rooms to which Robert replies "I can answer that - absolutely nothing!"
2011 Christmas Special: 1919-1920 Edit
Isis appears in the Christmas Special when Thomas hides her in a shack. His plan was to keep her hidden and then find her to gain Lord Grantham's trust, potentially causing him to be promoted to valet. However, his plan backfires when a village girl finds Isis and brings her to the Earl for a reward. However, the Earl sees that Thomas was searching for Isis and is touched. Thomas gains his trust and is hired once again.
Series Three: 1920 Edit
Isis occasionally appears in the background.
2012 Christmas Special: 1921 Edit
Tom Branson is holding Isis on her leash when the family leave for Scotland. Robert asks him to walk her a lot, saying she can get lazy. Later he is walking her when he goes to lunch at the Grantham Arms.
Series Four: 1922Edit
Isis appears in the background, such as during the performance of Jack Ross and his band members.
Later, when Lord Grantham leaves for America to visit his in-laws, he asks Tom to look after the women in the house, and especially Isis.
2013 Christmas Special: 1923 Edit
As with the Scotland visit, Tom Branson is left to look after Isis for a few days before he joins Lord Grantham in London. Upon arrival, the latter asks whether Isis is pleased to be in London; Branson responds that she is pleased to be with Robert, he was 'no substitute'.
Series Five: 1924 Edit
Isis appears in the background of several episodes lying on the floor and looking tired, sad and unhealthy.
Lord Grantham takes Isis to a specialist who diagnoses her with cancer. He can't bring himself to have her put down, so on what he feels is her last night, he lays her on his bed, between him and Lady Grantham so that she had "two people who love her and each other very much on either side".
Behind the Scenes Edit
- Pharaoh is played by a dog named 'Roly'. Lady Carnarvon’s dog did not like other male dogs in his territory, so Roly was replaced by a female dog named 'Ellie' to play Isis.
- The yellow lab that took over the part of Isis later during series three is named 'Abbey'. Abbey then went on to be in the 2012 Christmas episode, series four, the 2013 Christmas episode and series five. 
- The Yellow Lab was not bred until the middle of the 20th century, prior to that the closest in colour was the Golden Lab, which was more butterscotch in colour.
- Both dogs' names are references to Ancient Egypt, and were likely chosen to tribute the Earl of Carnarvon, who financed Howard Carter's expedition that eventually led to the discovery of the tomb of Tutankhamun (artifacts from the tomb are still at Highclere Castle).