CHICAGO (CBS) – A nun with a mission to help homeless women and children retired after over 30 years of service.

77-year-old Sister Therese O’Sullivan retired June 1 after providing three decades of shelter and drug recovery assistance to woman in Chicago.

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Sister O’Sullivan founded St. Martin de Porres House of Hope shelter, 6423 S. Woodlawn Ave, 33 years ago with Sister Connie Driscoll, CBS 2’s Sandra Torres reports.

“We opened our shelter in 1983,” Sister O’Sullivan said. “Our mission then was to help homeless women and their children.”

Angela Holman is one of those women Sister O’Sullivan helped.

Holman came to St Martins back in 2010 to overcome drug addiction.

“Life was pretty dark for me by the time I got to be at St Martins,” Holman said. “I was tattered and torn over 25 years of addiction.”

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With the help of Sister Therese O’Sullivan and others at the shelter, her life was transformed.

“My life was revolutionized right here,” Holman said.

It is women like Holman who have kept Sister O’Sullivan motivated all these years. But after more than three decades of service, it was time for her to retire.

“People said about me being here 33 years, ‘how could you do it,’” Sister O’Sullivan said. “And I say, ‘how could I not do it?’”

More than 4,000 women and children have benefited from the shelter in 33 years, with conseling, housing and job placement. Last year, the facility served 56 women and their children. Sister Therese O’Sullivan’s work will leave a lasting mark.

Sister O’Sullivan will be honored in a gala Thursday night for her 33 years of life-changing service.

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Although she is retiring, Sister O’Sullivan she said still plans to continue to work and reside at House of Hope.