Trick of the Moonlight

Stannis sat at his Painted Table with Maester Pylos at his shoulder, an untidy pile of papers before them. “Ser,” the king said when Davos entered, “come have a look at this letter.”
Obediently, he selected a paper at random. “It looks handsome enough, Your Grace, but I fear I cannot read the words.” Davos could decipher maps and charts as well as any, but letters and other writings were beyond his power. But my Devan has learned his letters, and young Steffon and Stannis as well.
“I’d forgotten.” A furrow of irritation showed between the king’s brows. “Pylos, read it to him.”

~ A Clash of Kings

“I am lowborn,” Davos reminded him. “An upjumped smuggler. Your lords will never obey me.”
“Then we will make new lords.”
“But…I cannot read…nor write…
“Maester Pylos can read for you. As to writing, my last Hand wrote the head off his shoulders. All I ask of you are the things you’ve always given me. Honesty. Loyalty. Service.” 

~ A Storm of Swords

He did not need Salla to tell him that he had risen too high. I cannot read, I cannot write, the lords despise me, I know nothing of ruling, how can I be the King’s Hand? I belong on the deck of a ship, not in a castle tower. He had said as much to Maester Pylos. […] “Read your history, Lord Davos, and you will see that your doubts are groundless.”
“How can I read history, when I cannot read?”
“Any man can read, my lord,” said Maester Pylos. “There is no magic needed, nor high birth, I am teaching the art to your son, at the king’s command. Let me teach you as well.”
It was a kindly offer, and not one that Davos could refuse. And so every day he repaired to the maester’s chambers high atop Sea Dragon Tower, to frown over scrolls and parchments and great leather tomes and try to puzzle a few more words. His efforts often gave him headaches, and made him feel as big a fool as Patchface besides. His son Devan was not yet twelve, yet he was well ahead of his father, and for Princess Shireen and Edric Storm reading seemed as natural as breathing. When it came to books, Davos was more a child than any of them. Yet he persisted. He was the King’s Hand now, and a King’s Hand should read.

~ A Storm of Swords

Davos knelt. “If I have offended, take my head. I’ll die as I lived, your loyal man. But hear me first. Hear me for the sake of the onions I brought you, and the fingers you took.”
Stannis slid Lightbringer from its scabbard. Its glow filled the chamber. “Say what you will, but say it quickly.” The muscles in the king’s neck stood out like cords.
Davos fumbled inside his cloak and drew out a crinkled sheet of parchment. It seemed a thin and flimsy thing, yet it was all the shield he had. “A King’s Hand should be able to read and write. Maester Pylos has been teaching me.” He smoothed the letter flat upon his knee and began to read by the light of the magic sword.

~ A Storm of Swords.

Davos shuffled through the letters slowly, reading each one several times, wondering whether he should change a word here or add one there. A man should have more to say when staring at the end of his life, he thought, but the words came hard. I did not do so ill, he tried to tell himself. I rose up from Flea’s Bottom to be a King’s Hand, and I learned to read and write.

~ A Dance with Dragons