Mice in Pentos
Varys started out as a thief in Myr, but after a rival thief informed on him, he fled to Pentos. There, Varys met Illyrio Mopatis, and together they formed a team. Varys spied on lesser thieves and stole from them, whilst Illyrio offered help to the victims of those thieves for a reward.
After a while, Varys stopped spying and stealing himself and instead started to train his "mice". Varys preferred small orphan boys and young girls who were quick and quiet. He taught them to climb walls, to slip down chimneys, and to read. When Varys explained to Illyrio how secrets were worth more than silver or sapphires, the mice started stealing letters, ledgers and charts. The mice were eventually taught to read the letters and leave them where they were.
Birds in King's Landing
King Aerys II Targaryen grew mistrustful of his heir, Prince Rhaegar Targaryen, his wife, Queen Rhaella Targaryen, and his Hand of the King, Lord Tywin Lannister. When word of Varys's talents reached the Red Keep, he was called from Pentos across the narrow sea to King's Landing to serve Aerys as the master of whisperers and spymaster.
Although no longer living in the same city, Varys and Illyrio Mopatis continued to work together. The Pentoshi magister provides Varys with his new spies, called little birds in King's Landing. It is hinted that the children who become little birds have had their tongues cut out to prevent them from telling their secrets to others. The birds are provided to Varys in those conditions. Varys's spies are able to navigate secret passages in the Red Keep.
A Game of Thrones
A Clash of Kings
Varys is warned by his birds about Shae, the whore Tyrion Lannister had tried to sneak into King's Landing, since his father, Lord Tywin Lannister, had forbidden Tyrion to take the girl to court with him.
A Storm of Swords
While questioning Sansa Stark about King Joffrey I Baratheon, Lady Olenna Tyrell demands her fool, Butterbumps, to sing as loud as he possibly can, to prevent others, including Varys's birds, from hearing anything that is being said. This is successful, as the one to tell Tywin about the secret plan to marry Sansa to Willas Tyrell is Petyr (informed by his spy Dontos Hollard), not Varys.
A Feast for Crows
Queen Regent Cersei Lannister, fearing that her brother Tyrion is hiding inside the hidden passages of the Red Keep after his murder of Tywin, does not realize the people she hears are actually Varys's birds behind the walls.
A Dance with Dragons
Varys sends one of his birds to fetch the new regent, Ser Kevan Lannister, and bring him to the chambers of Grand Maester Pycelle, whom he has already murdered. Varys mortally wounds Kevan, tells him of Aegon Targaryen, and has several of his little birds end Kevan's suffering with their daggers.
Varys: I must have gold, and another fifty birds.
Illyrio: So many? The ones you need are hard to find... so young, to know their letters... perhaps older... not die so easy...
Varys: No. The younger are safer... treat them gently...
Illyrio: ...if they kept their tongues...
Varys: ...the risk...
It is one thing to deceive a king, and quite another to hide from the cricket in the rushes and the little bird in the chimney.—Varys to Tyrion Lannister
—thoughts of Tyrion Lannister
It had to be the godswood. No other place in the Red Keep is safe from the eunuch's little birds... or little rats, as I call them. There are trees in the godswood instead of walls. Sky above instead of ceiling. Roots and dirt and rock in place of floor. The rats have no place to scurry. Rats need to hide, lest men skewer them with swords.
At night Cersei sometimes heard soft sounds, even in her own apartments. Mice in the walls, she would tell herself, no more than that.—thoughts of Cersei Lannister
They were all around him, half a dozen of them, white-faced children with dark eyes, boys and girls together. And in their hands, the daggers.—thoughts of Kevan Lannister
- A Dance with Dragons, Chapter 5, Tyrion II.
- The World of Ice & Fire, The Targaryen Kings: Aerys II.
- A Game of Thrones, Chapter 32, Arya III.
- Q&A Before/After reading ConQuest 44 (May 25, 2013)
- A Storm of Swords, Chapter 77, Tyrion XI.
- George R. R. Martin's A World of Ice and Fire, Varys.
- A Clash of Kings, Chapter 17, Tyrion IV.
- A Game of Thrones, Chapter 18, Catelyn IV.
- A Game of Thrones, Chapter 25, Eddard V.
- A Clash of Kings, Chapter 3, Tyrion I.
- A Storm of Swords, Chapter 12, Tyrion II.
- A Storm of Swords, Chapter 6, Sansa I.
- A Storm of Swords, Chapter 16, Sansa II.
- A Storm of Swords, Chapter 19, Tyrion III.
- A Storm of Swords, Chapter 61, Sansa V.
- A Feast for Crows, Chapter 32, Cersei VII.
- A Dance with Dragons, Epilogue.
- A Clash of Kings, Chapter 15, Tyrion III.
- A Storm of Swords, Chapter 1, Jaime I.