BOSTON (AP) – Martha B. Sosman, one of three Massachusetts Supreme Judicial Court judges who voted against the landmark decision legalizing same-sex marriage in the state, has died, the court said Sunday. She was 56.

Family members said the cause of death Saturday night was respiratory failure, according to a statement from Chief Justice Margaret H. Marshall.

Sosman was diagnosed with breast cancer in 2005 and had been participating in some cases by watching Web casts of oral arguments, reading legal briefs at home and talking with other justices and law clerks by telephone. She was treated by chemotherapy and radiation.

“Justice Sosman will be remembered as one of the great justices of the Supreme Judicial Court, despite her all too brief tenure on the court,” Marshall said in the statement. “She was admired and respected by members of the bar and litigants alike.”

Gov. Deval Patrick will appoint a new justice to serve on the seven-judge panel. A spokesperson said Sunday that Patrick will talk more about the process he will use to fill the vacancy after Sosman’s funeral services.

“She was a wise judge and a good personal friend,” Patrick said in a written statement. “She leaves a great void on the Court.”

Typically, the governor convenes a nominating commission to propose several potential justices and appoints one from that list. The justice would appear at a public hearing and then face a ratification vote from the Governor’s Council, an eight-member elected body that confirms judges, said Joan Kenney, a spokesperson for the Supreme Judicial Court.

In 2003, when a high court ruling made Massachusetts the first state in the nation to legalize same-sex marriage, Sosman wrote a strenuous dissent for the court’s minority. In her opinion, she belittles the majority’s advisory opinion, saying that it “merely repeats the impassioned rhetoric” of same-sex marriage advocates.

She said the argument to define same-sex partnerships as marriages versus civil unions was “a squabble over the names to be used.” To highlight her point, she quoted from Shakespeare’s Romeo and Juliet – “What’s in a name? That which we call a rose, By any other name would smell as sweet.”

In the majority opinion, Marshall chided Sosman, writing that she “so clearly misses the point that further discussion appears to be useless.”

In 2000, Republican Gov. Paul Cellucci appointed Sosman to the high court as an associate justice.

At the time, Cellucci hailed her as a “conservative” jurist who would react to decisions by lawmakers and not create state policy by loosely interpreting laws. However, many abortion foes protested the selection because of Sosman’s past service on the board of directors of Planned Parenthood.

Sosman, who was never married, is survived by her father and a sister, Nancy. A funeral has not yet been planned.