Tyland Lannister

Ser Tyland Lannister was a member of House Lannister and a member of the small council during the Dance of the Dragons.

History
Ser Tyland Lannister was a member of the small council in the final days of the reign of King Viserys I Targaryen. After his death, he was present in the secret meeting in which Queen Alicent Hightower, the newly widow of King Viserys, and Ser Criston Cole, the Lord Commander of the Kingsguard, conspired with the council to crown Aegon II Targaryen instead of Viserys's designated heir, Princess Rhaenyra Targaryen, and witnessed the death of Lord [Lyman Beesbury]].

In the books
In the A Song of Ice and Fire novels, there's no mention of Ser Tyland Lannister. He does appear in The Princess and the Queen and The Rogue Prince novellas and is mentioned as well in The World of Ice and Fire. Tyland was the younger twin brother of Lord Jason Lannister, the Lord of Casterly Rock, and the Master of Shipsfor King Viserys I.

After the death of King Viserys, Ser Tyland supported crowning Aegon II, citing that many of the lords that had sworn to defend Rhaenyra's claim were long dead after twenty four years and that he himself hadn't sworn any oaths - being a child at the time.

After the murder of Lyman Beesbury, Master of Coin, Ser Tyland was named the new Master of Coin and quickly moved to secure the royal treasury for the greens and divided it into four parts - one entrusted to the Iron Bank of Braavos for safekeeping, the second sent to Casterly Rock, the third to Oldtown and the remaining fourth kept by the greens for bribes, gifts and hiring sellswords.