BOSTON (AP) – Deval Laurdine Patrick was sworn in Thursday as the 71st governor of Massachusetts, the culmination of a longshot political campaign that also saw him become the state’s first black chief executive and only the second elected in the nation.

Amid springlike weather that embraced the state’s first outdoor inaugural, Patrick placed his hand on the Bible slaves gave to John Quincy Adams – the nation’s sixth president – after he helped free them for commandeering the ship “Amistad.” He then repeated the oath recited to him by Senate President Robert Travaglini.

“We meet today on a singular occasion, more than the passing of title and honor, more than the ritual transfer of the power of government,” Patrick, 50, said from the Statehouse steps to a crowd of thousands that stretched into Boston Common. “This is the occasion when the people charge new leadership to steward the public trust. It is a profound responsibility and I accept it humbly.”

Playing off the Amistad theme, he added: “I am descended from people once forbidden their most basic and fundamental freedoms, a people desperate for hope and willing to fight for it – and so are you. … This commonwealth, and nation modeled on it, is at its best when we show that we understand a faith in what’s possible and willingness to work for it. So as an American, I am an optimist, but not a foolish one. I see clearly the challenges before us.”

Patrick pledged to reshape the executive branch “to enable our public servants to concentrate on public service at the core,” and he urged municipalities to “enter into a new partnership” with state government.

“It’s time for a change, and we are that change,” Patrick said. “Let’s rebuild this City on a Hill and make it shine again.”

Aides plan an announcement a day for the first 30 days of the administration, starting next week. Patrick was scheduled to sit down with his Cabinet for the first time at 9 a.m. Friday. He has already pledged an “aggressive” legislative calendar and planned some undisclosed symbolic action Friday.

Worcester Mayor Timothy Murray also was sworn in as lieutenant governor by House Speaker Salvatore DiMasi. Murray will continue to hold both titles until Jan. 9, when he steps down as mayor.

In brief remarks, Murray said: “Today we affirm that we are one commonwealth. The concept of democracy and liberty that sprang from Massachusetts and helped create a nation still lives and breathes in its purest form in city and town halls across the state.”

Among those looking on were the grassroots supporters who helped propel Patrick to a 21-point victory on Election Day. Seated in chairs at the base of the Statehouse steps were members of the Legislature and four past governors: Michael S. Dukakis, William F. Weld, Paul Cellucci and Jane M. Swift.

Also observing was L. Douglas Wilder, who became the nation’s first black elected governor in 1990 when he was similarly inaugurated in Virginia. He now serves as mayor of the state’s capital city, Richmond.

Former Gov. Mitt Romney, who decided against seeking a second term, did not attend the ceremonies, having left the building Wednesday night after taking a tradition-laden “lone walk” down the Statehouse steps.

Romney, who filed papers Wednesday to form a presidential exploratory committee, stayed at his Belmont home before heading into his new headquarters in the North End to work on his campaign for the 2008 GOP nomination.

“I thought the governor’s address was fine and moving,” Romney said. “I’m delighted with his optimism and his hope to bring improvements to the commonwealth.”

Patrick was raised on the South Side of Chicago by a single mother. He first came to Massachusetts as a 14-year-old on a scholarship to prestigious Milton Academy. He went on to earn degrees from Harvard and Harvard Law School, serve a stint as President Clinton’s civil rights chief and also worked as counsel to two Fortune 500 corporations, Texaco and Coca-Cola.

Over the course of a 19-month gubernatorial campaign, Patrick claimed the Democratic nomination after beating an entrenched incumbent, Attorney General Tom Reilly, and businessman Chris Gabrieli, who spent $10 million on his campaign.

Patrick won the general election against Lt. Gov. Kerry Healey, who aired television ads arguing he should be “ashamed, not governor” for advocating for the parole of a convicted rapist.

With his installation, Patrick ended a 16-year run of Republican rule that began in 1991, when Weld replaced Dukakis in the Corner Office.

“You know, all good things must come to an end,” Weld told reporters before the inaugural. “For any given office holder, I’m one who thinks that two terms is plenty; maybe even a little too much.” Weld resigned from office amid his second term to wage an ultimately unsuccessful bid to become U.S. ambassador to Mexico.

Patrick started his day before dawn, continuing to work on his inaugural speech before making an unpublicized visit to Children’s Hospital to visit ailing patients and their families.

Afterward, he was whisked off in a motorcade escorted by State Police motorcycles to an interfaith service at the Old South Meeting House.

“I hope you can feel both the joy in this room and the sense of expectation that accompanies it,” said the Rev. Peter J. Gomes, a religion professor at Harvard University, Patrick’s alma mater. “You can’t do what you are about to do on your own. You will need a lot of help.”

Patrick insisted on the outdoor venue both to accommodate more people than could fit inside the building, and to emphasize the inclusiveness of his new administration.

Afterward, Patrick and Murray greeted the public at the Statehouse before traveling to a “youth inaugural” at the Shubert Theatre. The two planned to cap the day with a tuxedo-optional ball at the Boston Convention and Exhibition Center. The featured musical performer was renowned cellist Yo-Yo Ma.

Over the weekend, Patrick was scheduled to attend five regional receptions or inaugural balls, beginning Friday night in North Andover.