Alerie Tyrell is a daughter of House Hightower. She is the wife of Mace Tyrell, the Lord of Highgarden and the head of House Tyrell. They had two children, Loras and Margaery. She is the elder sister of Lynesse Hightower, the estranged wife of Ser Jorah Mormont. Her family was murdered during the destruction of the Great Sept of Baelor and her mother-in-law Olenna Tyrell subsequently became the de facto leader of House Tyrell until Highgarden was sacked by House Lannister and House Tarly, resulting in Olenna's death.
Behind the scenes
Alerie's status in the TV continuity has never been established as she never appeared or was even mentioned as being alive or dead. She didn't appear at her own daughter's two weddings. The only time she was referred to (without mentioning her name) was in the episode "The Bear and the Maiden Fair", when Sansa Stark discussed her upcoming marriage to Tyrion Lannister with Margaery; Margaery tried to console Sansa as best she could, by pointing out that Tyrion isn't the worst Lannister and would possibly be able to make her happy, even in a sexual way. In a naive manner, Sansa asked Margaery if her mother taught her insight in those matters, with Margaery's only reaction a smirking acknowledgement. Even the Tyrell actors said it was never clearly established what the status of Alerie was. The writers may have kept it deliberately vague to keep their options open as the story progressed. With the declaration in Season 7 that with the death of Olenna, House Tyrell is extinct, it seems most likely that Alerie simply died some years before the TV series even began.
In the books
In A Song of Ice and Fire, Alerie's family remains the same, except she and Mace have two other sons, named Willas and Garlan. She is described as tall and dignified and has long silver hair (presumably from age and not Valyrian heritage). She is younger than her husband. At a function, she refers to Olenna as "mother", but Olenna snaps that she would have remembered giving birth to Alerie, and that she is "only to blame" for Alerie's husband.
In the third and fourth novels, Alerie is actually present in King's Landing with most of the other Tyrells. She attends the Purple Wedding, and comforts Margaery when her new husband has been poisoned. She remains through Tywin's funeral and Tommen's wedding, and later leaves King's Landing with Olenna and Garlan, thus she is not involved in the following events at the capital.
Alerie's father is Lord Leyton Hightower. The identity of her mother is unclear: Leyton's fourth and current wife is Rhea Florent, but Alerie's mother might have been one of his previous wives. Gerold Hightower, Lord Commander of the Kingsguard during Robert's Rebellion, was Leyton's uncle - thus, through Alerie, the famed Ser Loras Tyrell is in fact the grandson of Gerold's nephew.
|Seat:||The Hightower, Oldtown||Lands:||The Reach|
|Title(s):||Lord of the Hightower · Voice of Oldtown|
|Ancestors:||Urrigon Hightower · Peremore Hightower · Lymond Hightower · Dorian Hightower · Runcel Hightower · Manfred Hightower|
|Current members:||Leyton Hightower · Lynesse Hightower|
|Deceased members:||Otto Hightower · Alicent Hightower · Gerold Hightower · Alerie Hightower|
|Lord:||None, extinct||Heir:||None, extinct|
|Title(s):||High Steward of Highgarden · Lord of Highgarden · Lord Paramount of the Reach · Warden of the South|
|Ancestors:||Garth Gardener · Harlen Tyrell · Lyonel Tyrell|
|Deceased members:||Luthor Tyrell · Mace Tyrell · Margaery Tyrell · Loras Tyrell · Olenna Tyrell · Tyrell lady · Alerie Tyrell|
|Household:||Mira Forrester · Sera Durwell|