Quantos anos tinha Theon Greyjoy quando foi trazido para Winterfell?

Desde que você fez esta pergunta para o Show, em Showverse, Theon tinha 8 anos quando foi levado por Lord Stark para Winterfell.

Theon: I'm a Greyjoy. We've been lords of the Iron Islands for 300 years. There's not a family in Westeros that can look down on us, not even the Lannisters.

Ros¹: And what about the Starks?

Theon: I've been Lord Stark's ward since I was eight years old.

Ros: A ward - that's a nice word for it.
_{Season 1 Episode 5 - The Wolf and the Lion}

Guia do HBO para espectadores também confirma:

As punishment and to ensure there would be no other uprisings, Robert forced Balon to surrender his only surviving son, Theon (then 8), for Ned Stark to raise as his ward at Winterfell.

_{1. Nome corrigido de Rose para Ros, graças a Skooba}

De acordo com os romances, ele tinha dez anos quando foi levado para Winterfell.

"I was a boy of ten when I was taken to Winterfell as a ward of Eddard Stark."
_{A Clash of Kings - Theon I}