Event: Petyr Baelish (Littlefinger) - Act of Betrayal (Political Wins)

Episode 5: Eastwatch at 51:24
Littlefinger has been using Maester Wolkan to dig through the Winterfell archives, portraying it as a command by Sansa Stark.

Maester Wolkan: "I found it, my Lord. It took some searching. Maester Luwin's archives are very thorough."
Petyr: "You're sure this is the only copy in Winterfell?
Wolkan: "Yes, my Lord."
Petyr: "Lady Stark thanks you for your service."
(Act of Betrayal)