In the
A Song of Ice and Firenovels, Arya later learns Wylla is a servant of
House Dayneof
Starfalland has been for many years. When she is with the
Brotherhood Without Banners, one of their members is the young Edric Dayne, the new head of House Dayne. He explains that Wylla was his wet-nurse at Starfall, and that she previously also nursed Jon (who is about four years older than Edric). He doesn't know how or in what circumstances Wylla met Eddard, because he was born a few years after Eddard and Jon left, and no one ever said more about it. Wylla was therefore alive for some time after Jon's birth, but it is unknown if she is still alive.
The novels make the mystery of Wylla truly being Jon Snow's mother more overt than in the TV series. Jon Snow is repeatedly noted for his striking physical resemblance to Ned at a young age, more so than any of Ned's trueborn sons - thus no one denies that Jon must have Stark blood in him.
Throughout the course of the novels, many characters mention rumors about other women who could be Jon's mother, or speculate about it themselves. Catelyn herself heard maidservants discussing the rumor that Jon's mother was Ashara Dayne of Starfall - Edric's own aunt, not just a servant. Ashara's brother was
Arthur Dayneof the
Kingsguard, whom Ned and his allies killed in the final confrontation of the war, the
Showdown at the Red Mountains. Afterwards Ned returned the Dayne ancestral sword
Dawnto Starfall out of respect, at which Ashara unexpectedly committed suicide by throwing herself off a cliff into the sea. The rumor was that Ashara didn't simply kill herself because her brother died in war (which happens to many women), but out of grief that her own lover had killed him. Catelyn asked Eddard about Ashara and Jon once early in their marriage: it was the only time Eddard ever truly became angry at her and frightened Catelyn. He said nothing, but commanded her never to ask about Ashara or about the identity of Jon's mother ever again, and indeed she never did afterwards. Even so this was only one of the more prominent of several rumors about the identity of Jon's mother. Others say that she was a fisherman's daughter in the Vale, where Eddard had been staying as a
wardof
Jon Arrynwhen the war broke out, and that he fathered Jon on her as he was fleeing back to the North to raise its armies after the Mad King killed his father and brother.
As in the TV series, the only woman that Ned himself ever identifies as Jon Snow's mother is "Wylla" - only once, when King Robert asked, and Eddard isn't in a position to refuse his king an answer. Ned also tells King Robert that he does not want to discuss Wylla any further with him since his adultery was his dishonor towards himself and
his wife.