But Aunt Petunia receives a Howler – a special enchanted letter – that says only, "Remember my last, Petunia" (2.217). By the final chapters of Book 5, Harry discovers that this Howler was sent by Professor Dumbledore to remind Aunt Petunia of her oath to give Harry a place to live.
One of Petunia Dursley's biggest secrets was the promise she made to Albus Dumbledore. When James and Lily were killed at the hand of Voldemort and Harry was dropped off on the doorstep of 4 Privet Drive, there was a letter accompanying him.
The fan asked the author if Aunt Petunia was a Squib (a non-magical person who is born to at least one magical parent) and Rowling replied: "Good question. No, she is not, she is not a Squib. She is a Muggle.
Dumbledore sent this to Petunia to remind her of the contents of the letter left on the porch with Harry when he was a baby that explained what happened and the protection Harry was under while in her home. This reminder caused her to stand up to Vernon and Harry go to stay.
This letter was written by Albus Dumbledore on 1 November 1981 to Petunia Dursley. The letter detailed the wards that would be created if she were to take in her nephew, Harry Potter, until he was seventeen.
Dumbledore responded saying that Petunia could not study at Hogwarts due to her being a Muggle and even though he responded kindly, Petunia felt hurt and left out. From that point on, Petunia wanted nothing to do with magic or the wizarding world and frequently called Lily a "freak".
Petunia never showed any love and affection at all towards Harry because he reminded her of Lily and the wizarding world. She treated him as a waste of space, giving him the cupboard under the stairs at first and making him do all the chores. She, along with Vernon, ignored most of Harry's birthdays.
No doubt Petunia would have been saddened by the news of Lily's death but those complicated emotions – grief, regret and unresolved jealousy – were probably buried in the distractions of housework, gossip and pandering to her son Dudley's every whim.
For the same reason Lily was a red head and Petunia was blond: by accident of genetics. Magical ability, like red hair, is a recessive mutation. It can appear spontaneously or be passed down from an ancestor. The more people in the family who do not have the mutation, the less likely it is to be expressed.
Writing on Pottermore, Rowling explains how their cruel treatment dates back to Petunia's jealousy of her sister Lily's magical abilities when they were growing up, and Vernon's dislike of anything out of the ordinary.
Lily Josephine Evans (30 January, 1960–31 October, 1981) was an English Muggle-born witch, a daughter of Marion Evans and John Evans, the younger sister of Petunia Evans and elder twin sister of Willow Evans.
As an unqualified wizard who didn't finish his education, Hagrid was not technically allowed to perform magic. And yet, the beloved gamekeeper seemed very magical.
Dursley pretended she didn't have a sister, because her sister and her good-for-nothing husband were as unDursleyish as it was possible to be. The Dursleys shuddered to think what the neighbors would say if the Potters arrived in the street.
Petunia tried to hit Harry with a frying pan which thankfully Harry dodged.
But Petunia may have been jealous because she felt Lily's magic made their parents think Lily was special and paid more attention to her. It's the old story of one sibling feeling left out or unequal and it led to Petunia despising Lily's magic and her sister and later her own nephew.
Dudley Dursley. Dudley Dursley is Vernon and Petunia Dursley's only son and Harry's first cousin.
Her last line there is, "You didn't just lose a mother that night in Godric's Hollow, you know. I lost a sister." Since Aunt Petunia usually prefers not to acknowledge Harry's mother at all, it's a surprisingly sweet moment. In the book, she uses her last words to say "Well — goodbye" to Harry.
Some maintain that Rowling is a Squib — a non-magical person unlucky enough to be born to a Magical family. Recall that his status as a Squib is why Hogwarts caretaker Argus Filch was always so bitter.
Petunia learned that Lily died by a note and a baby on her doorstep. How incredibly cruel of Dumbledore. The sisters may have been estranged, but they were still sisters. Dumbledore also dumped a baby on her without asking if it was okay, and then seemed to blackmail her into keeping Harry.
And the Dursleys didn't attend the Potters' marriage ceremony. "[Petunia] and Vernon chose not to attend Lily and James' wedding.
6 The Dursleys Kept Harry's Baby Blanket
Dudley found it in Aunt Petunia's belongings after she passed away and sent it to Harry. This insinuates that Petunia held onto it for years, in spite of her resentment toward the Wizarding World and Harry, because it was another piece of Lily.
Petunia and her younger sister, Lily, were close up until Lily began to show signs of being a witch. Petunia became very envious over her sister's newfound magical abilities. Their bond was destroyed as Petunia started to bully Lily to hide her jealousy.
"The first meeting between Lily, her boyfriend James Potter, and the engaged couple, went badly, and the relationship nosedived from there," Rowling revealed. Rowling adds that Vernon hated Harry because he saw father James in him, much in the same way that Snape does.
Harry and Dudley maintained a relationship:
The once-estranged cousins made amends after Dudley's admission that Harry wasn't a “waste of space” and remained on “Christmas-card terms” as they grew older. However, their relationship never blossomed into a true friendship.
Uncle Vernon and Aunt Petunia (who had secretly longed for magic herself) didn't see much of their nephew, for obvious reasons. Dudley, on the other hand, reunited with Harry a few times so that their children could play together. Their relationship was awkward, but this was a major change from when they grew up.