Matilde Ucelay Maórtua was born in 1912 in Madrid into a bourgeois, professional, and enlightened family, as the eldest of four sisters. Her father's family, Enrique Ucelay, of Basque origin, had held a prominent economic, political, and professional position in 19th-century Madrid, closely tied to political liberalism. Meanwhile, her mother, Pura Maórtua, also of Basque descent, came from a wealthy family as well. Though she lacked formal academic training, she possessed an insatiable desire to learn and was fortunate to travel extensively, visiting museums and architectural works.
The Ucelay sisters grew up in early 20th-century Madrid: they went for walks in Retiro Park and had private tutors for drawing, French, German, and music. Later, when the “Instituto-Escuela” was established, they were educated in the tradition of the Institución Libre de Enseñanza (Free Institution of Education)—a progressive educational model championed by their grandfather. This institution taught students to reason rather than memorize, took them on field trips to learn directly from nature, and, in a highly progressive move for the era, offered coeducational schooling. With this privileged upbringing, Matilde developed a keen interest in music and sports, eventually becoming an exceptional skier.
At the Instituto-Escuela, deep friendships were forged, and several marriages eventually blossomed, including Matilde’s own marriage to José Ruiz-Castillo. At the time, he was five years her senior and the son of a successful, self-made publisher who founded the Editorial Biblioteca Nueva, among other presses. Pepe later succeeded his father at the publishing house, printing works by the era's leading writers and intellectuals.
