Responding to the religious and educational needs of young women suffering the ravages of the French Revolution, Saint Julie Billiart, a peasant woman born in Cuvilly, France, founded the Congregation of the Sisters of Notre Dame on February 2, 1804. In the brief span of twelve years she saw the opening of many schools in France and Belgium and established the Mother House at Namur. She died there in 1816.

In 1840, a small band of sisters first came to America at the request of the Archbishop of Cincinnati where their work flourished, both attracting postulants to the congregation and students to their schools.

In 1856, Saint John Neumann invited the Sisters of Notre Dame de Namur to Philadelphia. They first settled in the parish of the Assumption and a few years later moved the school to Rittenhouse Square. The Academy of Notre Dame at Rittenhouse Square, fondly referred to as "The Square," educated generations of Philadelphia's girls and boys teaching them, in the words of Saint Julie, "what they need to know for life," emphasizing concern for others, the love of God, Our Lady and the Church. When space constraints began to impact on the school's growth, Sister Rosalia, the Provincial, accepted Cardinal Dougherty's suggestion that she purchase the Geist Estate in Villanova to house the high school division. Sisters and students arrived there in time for Christmas, 1943.

The school operated on two locations until 1967 when Rittenhouse Square finally closed. Today, after more than fifty years on the Villanova campus, the Sisters of Notre Dame de Namur continue to educate young women in grades six through twelve, carrying on a tradition of academic excellence permeated by the values Saint Julie espoused: simplicity, integrity, dedication and service. The Sisters of Notre Dame de Namur are an international congregation, with a presence on five continents.