The Hills were Episcopal missionaries from the United States, and they arrived in a country that was building itself from nothing. There was no functioning state, no settled capital, and almost no schooling for girls anywhere in Greece. The couple opened a classical school in their house near the Ancient Agora, and the demand overwhelmed them almost immediately. Crucially, theirs was the only school in the country offering education to women. That single fact would shape the institution for the next century and a half. In a city still clearing its own rubble, the most radical thing the Hills built was not a building. It was the idea that Greek girls deserved a classroom.

Word spread, and the school earned the patronage of some of Athens' wealthiest families. By 1834 it had won the approval of the Greek authorities, and King Otto himself suggested it add training to turn girls into teachers. The following year a proper building went up at the corner of Nikodimou and Thoukididou streets, the same site it occupies today, and with it came something Greece had never seen: a nursery school, the first kindergarten in the country. Frances Hill, known to her pupils simply as Mrs. Hill, ran an expanding constellation of schools at once, infant classes for the youngest children, a girls' primary school, a normal school for training teachers, and an industrial school that taught sewing and domestic skills to girls from the poorest families.

Not everyone welcomed an American missionary teaching Greek girls. In 1842, after a wave of anti-missionary attacks, the school was forced to close for the rest of the term. When it reopened the next year, the Hills had quietly narrowed their focus to the kindergarten, the girls' elementary school, and the industrial school, dropping the teacher training and the boys' classes. It was a retreat, but not a defeat. The elementary school grew so distinguished that its graduation ceremonies drew the dignitaries of Athens, and in 1869 Mrs. Hill reopened the teacher-training normal school as the Hill Institute, restoring one of the first such schools in the country. She kept administering the whole enterprise until her death in 1884.

The measure of a school is the lives that pass through it. One early pupil, Elisavet Contaxaki, lived with the Hills and was educated under Dr. Hill's own supervision; she became his assistant and later played a role in the Cretan revolutionary movement, moving among diplomats in Crete and Constantinople. In the 1880s a student named Sevasti Kallisperi sat in these classrooms before going on to become the first Greek woman to earn a university degree. The school outlived its founders by generations. Frances Hill's niece Bessie Masson ran it for thirty-four years after her aunt's death, and the family carried it forward through the twentieth century. The girls' high school finally closed in 1982, but the kindergarten and grammar school endure, still in family hands, still teaching in Plaka where it all began.