The Lord of Casterly Rock is also Warden of the West (I: 95)
Three million crowns is owed to the house by King Robert (I: 163)
Lannister house guards wear steel helms with golden lions on the crests (I: 320)
The Lannister lord styles himself Shield of Lannisport (I: 513)
The Lannisters are the wealthiest of the Great Houses, although the Tyrells can command more men (I: 680. SSM: 1)
The role of the wardens are to defend their assigned regions from invaders, and are in theory the supreme generals of their area so as to avoid disunity (SSM: 1)