Why did the Tarlys betray the Tyrells?

Because she had no authority over the Reach. Ignoring the sexism of the place, she was the widowed mother of the now dead Lord of the Reach, the basis of her power. The Tyrells are all dead now (so far as we can tell) and even then Olenna is a Redwyne.

What house is Olenna Tyrell from?

House Redwyne House

Olenna Tyrell
Nickname	The Queen of Thorns
Gender	Female
Title	Dowager Lady of Highgarden
Family	House Redwyne House Tyrell

When was Mace Tyrell born?

Mace Tyrell

Mace Tyrell by Amok©.
Predecessor	Luthor Tyrell (Lord of Highgarden) Stannis Baratheon (master of ships) Orton Merryweather (Hand of the King)
Successor	Aurane Waters (grand admiral)
Culture(s)	Reach
Born	In 256–263 AC, at Highgarden

Why was Lady Olenna killed?

However, some are wondering why did Jaime kill Lady Olenna on Game of Thrones? The simple answer is: because Cersei wanted him to. Despite many fans’ hopes, Jaime is still very much in love with Cersei, which was proven after they hooked up again for the first time in a long while during Sunday’s episode.

Are the Tyrells Andals?

Unlike most other Great Houses, the Tyrells never ruled as kings. Ser Alester Tyrell, the founder of the house, was an Andal knight and adventurer who showed such prowess at arms that he was named the champion and sworn shield of King Gwayne V Gardener, the last of the Three Sage Kings.

Which is the richest house in Game of Thrones?

At the start of a Game of Thrones, House Lannister of Casterly Rock was the richest house in Westeros, rivalled only by House Hightower of Oldtown. Following behind those houses are the Tyrells, Freys, Arryns, Redwynes, Martells, Royces and Manderlys.

https://www.youtube.com/watch?v=1uB3HiRe8zo