Mace Tyrell: "If I may..."
Olenna Tyrell: "Not now, Mace! Lord Tywin and I are speaking."
-Mace Tyrell is chided by his mother, Olenna, as he tries to interrupt her conversation with Lord Tywin Lannister.
Lord Mace Tyrell was the Lord of Highgarden and head of House Tyrell. He was the father of Loras and Margaery Tyrell, and the son of Olenna Tyrell. He initially supported Renly Baratheon's claim to the Iron Throne in the War of the Five Kings, but after Renly's death he successfully negotiated an alliance with House Lannister to support King Joffrey's claim to the throne, on the condition that his daughter Margaery would marry Joffrey, making her the new queen and giving House Tyrell the prestige of entering into the royal bloodline. He was appointed both Master of Ships and Master of Coin on King Tommen's small council.

He, along with his children, died during the Destruction of the Great Sept of Baelor, which was orchestrated by Cersei Lannister.