Birdy is a 14-year-old girl living in a 13th-century English manor in Stonebridge. Unusually educated for her time, she keeps a diary to record her daily activities and strong opinions. She passionately resists her parents' efforts to turn her into a docile lady, preferring the freedom to roam outdoors and care for her caged birds.

The country knight of Stonebridge and Birdy's father. He focuses on managing his lands and securing profitable marriages for his children. He frequently clashes with his headstrong daughter, often resorting to yelling or physical discipline when she ruins his betrothal plans.

Birdy's mother embodies the ideal medieval noblewoman. She executes the duties of the manor with grace and compliance, contrasting sharply with her daughter's rebellious nature. She endures a difficult pregnancy and gently tries to convince Birdy to accept the societal expectations placed upon women.

Birdy's handsome uncle has recently returned from the crusades. Though he speaks of the crusades realistically as dirty and poorly executed, he remains a heroic figure in Birdy's eyes. He struggles to adapt to the restrictions of medieval society upon his return home.

A wealthy older nobleman from the north who seeks a new wife. Described by Birdy as uncouth and possessing terrible manners, his high status and substantial assets make him highly appealing to Lord Rollo. This positions him as the primary threat to Birdy's freedom.

The son of the wealthy nobleman Shaggy Beard. Unlike his coarse father, he is rumored to possess better manners and intellect. He sends Birdy a thoughtful gift of a dagger, showing a quieter approach to courtship.

The manor's goat boy and Birdy's closest confidant. Despite having a physical disability, he possesses a sharp mind and dreams of becoming a scholar. He acts as a grounded, practical counterweight to Birdy's impulsive schemes.

Birdy's best friend, a young noblewoman subject to the same strict marital expectations of their class. She shares dreams with Birdy but demonstrates a greater willingness to adapt to the marriages arranged for her by her family.

One of Birdy's older brothers. He lives at an abbey studying to become a monk. He encourages Birdy to channel her impulsive energy into writing a diary, providing the structure for her self-reflection.

Birdy's least favorite brother, whom she views as abominable and constantly strutting. He holds traditional views about men and women, often teasing his sister, though he occasionally displays unexpected moments of kindness.

Another of Birdy's older brothers who works in the king's service. He returns home occasionally for holidays, bringing news and trends from the royal court, such as the fashion of choosing a personal profanity.

Birdy's nursemaid, tasked with the difficult job of teaching her charge how to spin yarn and behave like a proper lady. She frequently loses her patience with Birdy's rebellious antics and tomboyish behavior.

An older, wealthy widow who marries Uncle George. She is a cheerful vegetarian with a deep love for animals. Having been struck by lightning years ago, she occasionally exhibits symptoms of mental illness, such as playing imaginary instruments.

A young boy sent to be fostered by Lord Rollo. He initially catches Birdy's eye with his good looks, but his lack of interest in learning and mean-spirited behavior quickly break her infatuation.

A relative of Lady Aislinn who visits the manor. He is an eccentric older man working on a history of the world in Welsh. He is deeply interested in obscure historical and religious mysteries.

A young female visitor to the manor who serves as a direct contrast to Birdy. She is prim, proper, and perfectly embodies the submissive ideals expected of medieval women.

A cousin of the king who visits Castle Finbury. Contrary to Birdy's expectations of an adventurous royal, Joana is an older woman burdened by chores and duty, though she possesses a keen insight into people's characters.

The manor's milkmaid. She represents the slightly greater personal freedom enjoyed by the working class, as she is able to choose her own husband, though still bound by financial constraints like dowries.

The village baker who marries the milkmaid Meg. Their loving, straightforward union provides a clear contrast to the political marriages arranged among the nobility.

Birdy's newborn younger sister, whose difficult arrival brings intense anxiety to the family. She is named after the deceased queen, the Virgin Mary, and Birdy herself.