The school that opened 100 years ago as the Charles E. Ellis College for Fatherless Girls is one of those lost Philadelphia institutions, whose lessons still teach, though in ways its namesake benefactor didn’t quite plan.

Ellis was started by a rich public-transit contractor, who followed in the tradition of Stephen Girard and Milton Hershey, pioneering Pennsylvanians who, failing to establish family dynasties, left fortunes and built charity boarding schools to meet great societal needs. (The tradition continues, albeit in an up-market way, as this generation’s Perelmans, Singhs and Vageloses endow medical- or engineering-school blocks.)

The Ellis boarding school housed up to 300 middle school and high school girls, not in a walled city-within-a-city like Girard’s North Philly acropolis, but on a green half-square-mile in Newtown Square, on the edge of the Main Line.

Like Girard, the buccaneer shipper-banker-industrialist who dictated controlling instructions for the boys’ school at his 40-acre compound, Ellis limited enrollment only to white, fatherless children.

The school finally enrolled African American girls in 1970, and closed seven years later, after trustees led by the boss of the former Provident National Bank (now PNC) persuaded the head city Orphans’ Court judge that Ellis’ cash was starting to run out, and that adding paying students, or even merging with Girard, wouldn’t save it.

Students, teachers and graduates fought the shutdown. But leaders of the alumnae group, who will gather this weekend as they do every five years or so, have come to believe in hindsight that the trustees may have done the best thing -- given the ongoing use of Ellis’ legacy since the closing (see below), and the fate of the charity boys’ schools that it copied.

“It was a protective environment,” said Lucy Cascioli, a nursing clinical educator at Lehigh Valley Hospital and an organizer of this year’s reunion. She and other graduates will gather early Saturday at their old dorm halls and seek familiar traces of playing fields and garden groves at the redeveloped campus, now an office, housing and retail center built by Dan DiLella’s Equus Partners, before adjourning to Springfield Country Club.

After her father’s death, Cascioli, then 12, passed academic and psychological tests to enroll in Ellis’ class of 1976. Her mother worked nights, and “was concerned about me spending a lot of time alone.”

Her brother hadn’t much enjoyed Girard. But Ellis, with its supervised night study halls, “interesting characters” who served as residential housemothers, “phenomenal” feminist teachers, and male presidents who served as patres familias, gave Cascioli stability and offered a “family” that would have been tough for her widowed mom to deliver on her $1.65 hourly hospital wages.

The mission evolved: Earlier girls were taught to cook and sew. But by the time she was there, “it was always assumed that you would apply to college.”

“Ellis constantly had to defend itself,” says Carolyn Aderson Kilgour, ’63, a retired university instructor. Even in its heyday after World War II, “they would call Ellis ‘the experiment,’ perhaps because it was for girls. I thought it was unfair.”

Cascioli remembers marching in protest of the threatened shutdown. But by the 1970s, she knew, almost “no one went to boarding schools anymore."

“With government payments, social services,” and more jobs for women at better pay, “mothers didn’t need to send their girls to a school like this,” said Kilgour.

Girard College, and the Milton Hershey School east of Harrisburg, whose chocolate-magnate founder used Girard as a model, faced some of the same pressures.

Ellis had a private board, but the boys’ schools are quasi-public and politically connected: Hershey, with a $14 billion endowment that rivals that of the much larger University of Pennsylvania, operates with the oversight of elected attorneys general who have helped defeat efforts to broaden its charitable activities. Its struggles with high turnover, staff miscues and insider deals have been documented in my colleague Bob Fernandez’s reporting and in his 2012 book, The Chocolate Trust.

Girard is controlled under the Board of City Trusts, a mix of elected officials and appointees who resisted calls to close that aging campus and shift funding to city schools or other programs. Much of the income from its $286 million endowment -- invested idiosyncratically in Girard’s old hard-coal mines, Wall Street funds, and direct loans to Center City developers -- is consumed by campus maintenance. Enrollment, once 2,000, is about 300, and kids are sent home on weekends to save cash.

With a private board -- as well as a smaller endowment -- the Ellis School gave up on its founders’ dream comparatively early. But it has enjoyed an afterlife that might serve as a model for other charities that outlast their missions.

The Charles E. Ellis Trust for Girls recorded a deficit in the school’s last years, spending down its founder’s legacy. The property was sold for $6.1 million, to Arco Chemical Co., whose CEO, Robert O. Anderson, had been one of the 16 Ellis trustees, according to Thomas DiFilippo, who wrote a history of the school, and who told me in an interview that Arco’s interest gave its boss an incentive to support the school’s closing. Arco successor Lyondell later divided the Ellis property between SAP, the German software firm which built its U.S. headquarters there, and Dan DiLella’s BGP Development Co. (now Equus), which has added offices, stores and homes.

By 1982, five years after the closing, the Ellis trust worth $10 million, rising to $44 million this year -- a little ahead of the inflation rate through that period -- while paying out the standard 5 percent or so.

The trust expects to give $1.9 million in grants to 500 Philadelphia girls from families with modest means. The grants, which average $3,800, can be used for tuition in private and Catholic high schools and for “exciting and meaningful experiences” for public and charter high school girls, according to Sara Woods, head of Philadelphia Futures, the nonprofit that runs the grants. Tax records show that the trust has spent $500,000 or so more in each recent year on programming, investment, legal and other fees.

The visions spelled out by founders of charities, like their businesses, erode in changing times. The Ellis trustees adapted by shutting a long-beloved institution so that the rich old public contractor’s money could continue in his broad purpose of helping girls find their way forward.