OAKLAND -- Former California state Sen. Nicholas C. Petris was a strong speaker whose gentlemanly manner could cross party lines to get laws like a landmark civil rights act for the mentally ill passed.

Petris, a Greek-American born in Oakland who went to kindergarten speaking mostly Greek, graduated from Stanford Law School and spent almost 40 years representing constituents in the California Legislature, died Wednesday in Oakland. He was 90.

Petris was a powerful force in state government, holding his seat in the Assembly from 1958 to 1966 and the Senate from 1966 to 1996 until he was termed out. Colleagues say Petris was kind and principled, a liberal who could work with Republicans to pass groundbreaking legislation. He not only championed the rights of the mentally ill, but he also worked with Save the Bay to protect the San Francisco Bay from development and championed laws prohibiting smoking in California buses and airplanes. The issues he worked on were modeled across the country, sometimes around the world.

"I was deeply saddened to hear about the passing of my dear friend Nicolas Petris. He was a steadfast friend and provided wise counsel to me throughout my time in the California Legislature," U.S. Rep. Barbara Lee, D-Oakland, said in a statement Friday. "He will always be remembered as a compassionate and vibrant champion, especially in his efforts to develop more accessible and quality mental health services with the Lanterman-Petris-Short Act. He will be deeply missed."

The Lanterman-Petris-Short Act gave the mentally ill their own bill of rights. Before that, some mentally ill Californians were "warehoused" indefinitely in state mental institutions without due process or trial.

"You could be put in a state facility for the rest of your life without any judicial review," said Valerie Bradley, president of Human Services Research Institute, who worked with Petris in the 1960s and '70s.

The act gives legal rights to people with mental illness, requiring judicial review after three days of being involuntarily held at a mental health facility. People who are held have to be a danger to themselves or others or gravely disabled.

"It was really a growth out of the civil rights movement for people who are affected by mental illness," Bradley said.

Petris also worked on legislation that prevented San Francisco Bay from being filled for development. Before working with the grass-roots organization Save the Bay, one-third of the bay had been filled in or diked off and there were aggressive plans by businesspeople to fill in 60 percent of what was left by 2020.

"What would have been left would have basically been a narrow river for navigation instead of a wide bay that we have now," said Save the Bay Executive Director David Lewis. "It would have been a pretty dramatic difference."

Petris formed an alliance with Save the Bay volunteers, mostly women with no political power, in the 1960s and co-sponsored the McAteer-Petris Act, which established and governs operations of the San Francisco Bay Conservation and Development Commission, a board that served as a model for other coastal zone management agencies.

"You have to remember there was no such word as an environmentalist at this time," Lewis said. "There was no history of doing this kind of thing. We needed Nicholas Petris and other people to step up and do the work inside the Legislature that was not easy to do."

Petris was raised bilingual, entering kindergarten speaking mostly Greek. He graduated from McClymonds High School and UC Berkeley. He served in World War II where he learned Japanese. He eventually graduated from Stanford Law School in 1949 and worked as an attorney in Oakland.

Petris was active in the Greek Orthodox Church, serving as president of the congregation. He was also a founding member of the board of trustees for the Oakland Museum of California.

California State Treasurer Bill Lockyer said Petris was one of the most liberal lawmakers in the Senate who consistently advocated for consumers, the environment and the poor. He was responsible for laws that made tax assessments more equitable and authored the law that required infants to travel in car seats. Often he would author bills years before issues were debated by the public, a move so common his staff called it the "Petris Gap."

Lockyer, who considered Petris his mentor, said Petris never showed anger and always tried to get along with everybody.

"He was extraordinarily gentlemanly," Lockyer said. "He was always diplomatic, whether he was speaking to colleagues, the public, staff members or lobbyists."

Petris was married to Anna Vlahos for more than 60 years. She preceded him in death. They did not have children. Together they survived the 1991 Oakland hills firestorm, but Petris lost his beloved library in the fire Lockyer said.

"He was a voracious reader," Lockyer said. "Thousands of books were destroyed in that fire."

After the fire, state Sen. Arthur Torres asked everyone in the Senate to bring a book to restock Petris' library. Many brought more than one.

Petris was honored by the University of California with an endowed chair in Greek classical studies, which is currently supporting a full-time faculty member in Greek art history. Also, $2 million from the settlement of a consumer protection antitrust lawsuit established the new Nicholas C. Petris Center on Health Care Markets and Consumer Welfare in the School of Public Health at UC Berkeley, which provides education on the changing health care system in California. A UC scholarship is annually awarded to a graduating senior at McClymonds High School.

Petris is survived by his brother Gus Petris, his cousin and long-term caretaker Noula Vlahakis and a host of nieces and nephews.

Viewing of Petris' body will be at 7 p.m. Monday at the Greek Orthodox Church, 4700 Lincoln Ave., Oakland. His funeral will be at 11 a.m. Tuesday at the same church.

In lieu of flowers, Petris' family requests mourners to make a donation to the Greek Orthodox Church and specify the Senator Petris Greek Language and Cultural Fund or donate to the UC regents as a gift to the Petris Center in the School of Public Health at the university.