Who is Crispin's mother?

Asta is the name of Crispin's mother. Sadly, before the novel even begins, Asta is dead and Crispin mournfully attends her funeral with only a priest at his side. Crispin had nobody but his mother in his life, so when she passes away, he is left with nothing. Having been left with the titular cross of lead (which has writing on it that Crispin cannot read), Crispin begins to question his mother's true identity. He never knew his mother could write or read, since she never told him so and never taught him how. At one point, Crispin thinks,

If there was one person I thought I knew, depended on, and trusted utterly, it was my mother. Yet I had been told things that said I did not know her.

As the novel progresses, Crispin quickly learns his mother to have a history that he could never have expected. She is actually royalty, the daughter of Lord Douglas, who became pregnant with the son of the cruel Lord Furnival. Crispin, then, is Lord Furnival's son, a fact which makes Furnival furious. Crispin's mother hid the truth from him in order to protect him, and, while many others, such as Father Quinel, know the truth of Crispin's identity, they keep it a secret from him at his late mother's request.