Ann Allosso says she was really too old for this type of thing.

Every Friday this past summer, the 73-year-old Allosso slipped flyers under doors in the Chapman Arms apartment buildings—a total of fifty units, four floors, and one rickety elevator. Every Monday, Allosso—who calls herself “the mother of the building”—led the meeting advertised on the flyer in the Chapman’s lobby.

Each week they discussed the same issue: The Chapman Arms building, located on Mt. Auburn Street, was on the market for the first time in nearly three decades, and it seemed likely that the building’s new owner would eliminate Chapman’s affordable housing units.

Chapman had been a mixed-income housing complex since 1986. That year, 25 units became affordable units, rented out at a markedly lower cost, while its twenty-five other apartments remained at market price.

When the Chapman went up for sale last year, the building’s location attracted many potential buyers, eager to turn a profit. Tenants like Allosso, unnerved by the circling would-be landlords, were afraid that they would be displaced from their homes.

“I didn’t have the least bit of hope,” says Allosso, who has lived in the same reduced-rent apartment at Chapman Arms since 1986.

But last month, Harvard, which owns the land on which Chapman sits; the city of Cambridge; and Homeowners Rehab, Inc., a local nonprofit dedicated to preserving affordable housing, banded together and forged a plan to save the building by preserving it under Massachusetts’s Chapter 40T, extending the guarantee for affordable housing for 50 more years.

According to Allosso, residents were overjoyed when they heard that Chapman would retain its mixed-income status, a resource made scarce in Cambridge by the multitudes of individuals seeking it.

“We needed a quick engagement between Harvard University and Homeowner’s Rehab, and from my mouth to God’s ear, that’s what happened,” Allosso says.

“THE CRAIGIE”

Situated next to a Harvard office building and across the street from the Mt. Auburn post office, Chapman Arms looks like most of the buildings in Harvard Square: red brick, white trim, historic, nondescript. With its entrance tucked away on one of the Square’s many side-streets irrelevant to undergraduate student life, the Chapman is effectively in the Harvard bubble but at the same time out of sight. Vines have climbed their way up the building’s brick facade, and the number four is the building’s sole mark of identification.

But Chapman’s innocuous appearance belies the diversity of its residents and the building’s storied past.

“We have Muslims, we have Ethiopians, we have students, the elderly, the young. We have everything,” Alloso says.

Alloso adds that mixed-income pricing makes the Chapman Arms community especially diverse. Most of its market-rate tenants are students at the Harvard School of Education and Harvard Business School. Tenants in low-income run the gamut from retirees to young immigrant families.

Chapman has a long legacy of providing affordable housing in the Square. In the early 1900s, the building served as an undergraduate dormitory, containing 36 apartments, to provide affordable housing to students.