Having done this for both my recently-completed novel and my work-in-progress, I thought I would do it for my published novel as well. I do believe this was even harder than Wordcrafter's; I didn't have any possibilities when I started, but here is what I dug up. (Also, please forgive the severe lack of period-correct clothing. You try to find actors wearing fifteenth century clothing on their IMDb pages.)
Note: Mild spoilers ahead. Nothing very major, though, I trust.
Fiona is the daughter of a lesser English nobleman, and has lived all her life in a secluded manor just on the English side of Wales. She is little more than a child still, but her simple life is turned on its head when her brother, Giovanni, leaves England with Henry V's army. Before his departure he speaks to Fiona, not for the first time, of her need for something more than being part of the Church and attending Mass; showing her his cross pendant, he tells her that it will bring her peace. But she is quite comfortable in her worldly sort of peace, and laughs him off.
Then Giovanni is killed at the Battle of Agincourt and his body brought back home to England - without the cross. Mad with grief and believing she has had a sign from God, Fiona sets out across the Channel and a desolated France to find and regain her brother's silver cross.
Fiona is stubborn and naive, but also tenacious and, driven on by an emptiness inside herself that she must fill, capable of withstanding a great deal. She will stop at nothing to gain the peace her brother spoke of.
Giovanni is Fiona's older brother and only sibling. Since their father's mental and bodily failure several years ago, he has run the manor and provided for the family. Unlike most of Christendom at that time, he is a devoted follower of Christ and believes that salvation is something more than going through the motions; although Fiona does not know enough about the world beyond the manor to realize it, Giovanni is a Lollard. He does not believe in Henry V's campaign against France, but he joins the army in obedience to his sovereign.
Pierre [lord of gallandon]
Fiona stumbles onto Pierre's land accidentally, but "accidents" have no influence with the master of Gallandon, and Fiona finds herself a servant to his family. Pierre is the first-born son of the Duke of Alençon, but he is also illegitimate, which means he is not in line to inherit his father's wealthy estate; instead, the French crown granted him the marshy estate of Gallandon. Determined to improve his situation and make a name for himself, Pierre moves on to "plan B" - a good marriage. But he finds himself out of luck in that quarter as well, as the wife he gets has no titles and, in fact, is not even French.
Pierre looks older than he actually is, and maintains that appearance by his manner of speaking and dressing. His insecurities and his obsession with bettering himself make him harsh, but he is in fact little more than a boy. He fought in the Battle of Agincourt and, what is more, made it back alive to tell the tale.
Leah is of Germanic descent, without a drop of French blood in her veins, and is the daughter of a merchant. Pierre was tricked into marrying her, but when he discovered the fact, he was decent enough not to annul the marriage; however, their relationship is an uncomfortable one. Leah's muteness puts her at a distinct disadvantage, too, and one of Fiona's duties as Leah's personal maid is to translate for her. In serving her (a humiliating turn of fortune for a nobleman's daughter) Fiona gradually finds Leah to be something more than "the enemy"; she is beautiful with a beauty that comes from inside and shines out of her, and Fiona becomes devoted to her as a friend.
Christopher, Leah's brother, was the force behind her alliance with Pierre. He is a fortune-hunter, like Pierre; but unlike Pierre, he has no scruples about it and has little interest in working to earn his bread. He has no interest in war, no interest in owning land; he lives by deceit, and does it well. He is allied with neither France nor England and has never fought in any of the battles. Fiona first crossed paths with him at a French inn and then meets him again at Gallandon, and she fears him as she fears the Devil - or more.
(Remember, The Soldier's Cross and Jenny's The Shadow Things are both on sale through April. Purchasing with the PayPal button on the sidebar will get you an autographed copy of each book.)