In an historic vote lawmakers on Thursday formally named California Rep. Nancy Pelosi as the first female speaker of the House, making her next in the presidential line of succession after the vice president.

The leadership elections were part of a day full of pageantry marking the convening of the 110th Congress. The Senate's new members were sworn in, too, and both chambers began getting to work, including the introduction of bills that are part an aggressive Democrat-led agenda for the first 100 working hours.

In the House, Pelosi, 66, received a standing ovation after being elected speaker. A committee was then organized to escort her out from and back into the chamber for formal recognition. Taking the gavel from the new House Minority Leader John Boehner, Pelosi, frequently interrupted by loud applause, told members: "I accept this gavel in the spirit of partnership not partisanship, and look forward to working ... with you on behalf of the American people.

"In this House, we may belong to different parties, but we serve one country. We stand united in our pride and prayers for our men and women in uniform. They are working together to protect the American people, and we, in this Congress we must work together to build a future worthy of their sacrifice," she said.

Pelosi's rise to the speakership began in 2004 when she was elected by her fellow Democrats to be House minority leader. After Democrats won control of the House in the Nov. 7 election, they unanimously chose for the top spot the Catholic mother of five from a Baltimore political family. Thursday marked the beginning of her 11th term in Congress.

Before introducing Pelosi formally to the House, Boehner took time to mark the history of the occasion.

"In a few moments, I'll have the high privilege of handing the gavel of the House of Representatives to a woman for the first time in American history. For more than 200 years, the leaders of our government have been democratically elected. And from their ranks, our elected leaders have always selected a man for the responsibility and honor of serving as speaker of the House. Always, that is, until today. ... Today marks an occasion I think the Founding Fathers would view approvingly," Boehner said.

Thursday's activities began with the scripted pageantry that accompanies each new Congress. Children in their Sunday best stood with their parents and grandparents on the House floor holding hands as the House chaplain offered a prayer. Some lawmakers could be seen wiping tears from their eyes before the body pledged its allegiance to the U.S. flag.

After lawmakers nominated the Democratic and Republican leaders of the House, the clerk took a roll call vote, which resulted in Pelosi's election to the speakership as well as Rep. John Boehner's election as House minority leader, the top Republican seat. Pelosi received 233 votes and Boehner received 202, equal to the current division of Democrats and Republicans on the south side of the Capitol.

The official handover of power from Republicans to Democrats came amid conflicting pledges of bipartisanship. House lawmakers planned to plunge immediately into a schedule that aspires to get several legislative items completed in the first 100 working hours. House Republicans claimed they were being excluded from the legislative process while in the Senate the GOP leader offered pledges of cooperation from the newly-minted minority.

In the Senate, where members generally show much more comity, new Senate Majority Leader Harry Reid cast a bipartisan tone while outlining the Democratic agenda for the first part of the year and proceed to introduce 10 bills that will all be sent to committee hearings before they make it to the floor for debate.

"Last November, the voters sent us a message — Democrats and Republicans. The voters are upset with Congress and the partisan gridlock. The voters want a government that focuses on their needs. The voters want change. Together, we must deliver that change," Reid said.

Reid's remarks were followed by those of new Senate Minority Leader Mitch McConnell, R-Ky.

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After speaking, Pelosi took her oath of office and in turn administered the oath to the rest of the chamber. The moment, however, was interrupted by a question from Rep. Rush Holt, D-N.J., who asked whether any of the day's proceedings would be affected by lawsuits filed in the recount efforts for Florida's 13th Congressional District.

Democrat Christine Jennings is fighting to take the seat from Vern Buchanan, the Florida Republican who was seated Thursday. Pelosi said that the proceedings would not be affected and would be handled later.

President Bush also offered his congratulations to the new leaders in an afternoon phone call.

After their official oath in the House chamber, members began posing for individual photos documenting the moment.

Of note, Keith Ellison, a Minnesota Democrat and the first Muslim elected to Congress, took his photograph swearing his loyalty to the U.S. House on a Koran once owned by former President Thomas Jefferson. He was surrounded by a large group of family and supporters.

Last month radio host talk show Dennis Prager criticized Ellison for not using the Christian Bible, which Prager said is the traditional book used by U.S. lawmakers to take their oaths. It ignited a national media debate over religion and government before Ellison even took office.

Speaking to ABC News, Ellison, who converted in college, said he hoped that his election to the House will help Muslims feel like they are part of U.S. society, but his focus is on secular domestic issues and getting out of Iraq rather than spreading Islam.

"I mean, sure, I'll use the Koran. I mean, it's the scripture that I read every day and it's the book that I draw inspiration from," he said. But, "all the religious stuff is going to be less important than those bread-and-butter issues that people care about every day."

Pledges of Bipartisanship

While both the House and Senate were convening at the same time, the divide in the Capitol between the two chambers is often much more than geographic. The House of Representatives, often referred to as the "People's House," operates more with arm-twisting and peer pressure than the smaller Senate, which is considered a more deliberative body built on compromise and consultation.

With the House only needing simple majorities of 218 votes to pass legislation, the Senate often must surmount the filibuster-proof 60 vote threshold to pass controversial bills, requiring closer cross-aisle relations than in the House.

Those differing styles presented themselves even before Congress convened as top Republican and Democratic senators appeared before cameras to pat each others' backs while House lawmakers threw around charges of exclusion and partisanship.

In front of a group of reporters gathered near the Senate chambers just after a meeting of Republican and Democratic lawmakers, Reid and McConnell stood side by side and pledged renewed cooperation.

"Sen. McConnell and I believe this is a new day in Washington, that our efforts are going to be to work in a bipartisan basis, in an open fashion, to solve the problems of the American people," Reid said.

"I think Harry's got it right. This opportunity we had in the Old Senate Chamber was a chance for many of our members to express some of their quiet frustrations that we get past the level of partisanship that we've witnessed in recent years and develop stronger personal relationships, as well as work across party aisles," McConnell added.

Saying they would work on a number of issues including ethics and lobbying reform and the Iraq war, the two then walked away from the microphones, Reid chatting into McConnell's ear and resting his hand on the Republican's shoulder.

On the House side, members did their part to pledge cooperation, but those claims were clouded by Republican charges that Democrats already aren't living up to their campaign promises.

"I think they're getting off to a bit of a rough start," said incoming House Minority Leader John Boehner of Ohio

"In 1994 when we took control of the House, 12 years ago, it wasn't that — we wanted to treat Democrats the way we had asked to be treated. And, frankly, that's what we did. What we really expect out of the Democrats is for them to treat us as they would like to have been treated," Boehner said.

But he added, "Republicans on Capitol Hill want to work with Democrats to deal with the issues that the American people sent us here to deal with."

A few minutes later, House Majority Leader Steny Hoyer of Maryland called Boehner his friend and denied that his party was trying to shut down Republicans in the first 100 hours of Congress, the time frame Democrats imposed on themselves to enact a list of changes.

"I don't think we want to shut them down in the first 100 hours. What we want to do in the first 100 hours is do exactly what we promised the American people that we would do and that we debated over the last six months," which includes the ethics and fiscal reform, homeland security changes, increasing the minimum wage and other changes.

"First 100 Hours"

Leading up to the opening session, Democrats this week distributed the latest outline of their "first 100 hours" agenda, which puts ethics and open government reforms at the top of their priority list to accomplish. The agenda also includes adopting the remaining recommendations of the Sept. 11 commission, raising the minimum wage, promoting stem cell research and renewable fuels while ending what Democrats saw as giveaways to the energy industry, and reducing Medicare prescription prices and student loan costs.

Over in the Senate, Reid said the first change of the new session will be a five-day work week, up by an average two days per week over the last session. He said that he and McConnell would be co-sponsoring the Senate counterpart to the ethics legislation planned to move in the House.

House Democrats introduced a sweeping package of ethics reforms that includes more limits on lobbying and congressional travel and more transparency on obscure procedures that allow power to concentrate in the hands of a few.

"The first thing, of course, we're going to do as you know is adopt rules which will provide for integrity, civility and fiscal responsibility in the House of Representatives," Hoyer said Wednesday.

Rep. Louise Slaughter, D-N.Y., chairwoman of the Rules Committee, which determines procedure for bills going to the House floor, sponsored the package. Among other items, it contains proposals to open up debate on lawmakers' home-state projects, known as earmarks but more frequently decried as pork-barrel spending.

"We're going to restore openness, integrity and honesty in Congress, and we'll hand the keys of the government back to the American people," Slaughter said Wednesday.

"The status quo has permitted some members of Congress, with no transparency and accountability, to provide favors to special friends through earmarked special projects — putting special interests ahead of the public interest. The American people deserve to know who is sponsoring earmarks to begin to stop the cases of flagrant abuse of earmarks," the Democratic materials say.

The Democrats' ethics reform plans include:

• Ban gifts and meals from lobbyists and organizations that hire them, and require members of Congress and their staffs to pay market price for tickets to sports and other entertainment events;

• Ban members of Congress from accepting lobbyist-paid or arranged travel; No campaign or taxpayer money can be used to pay for travel on non-commercial, corporate jets;

• Require certification and pre-approval for travel that is paid for by groups that fall outside the lobbying restrictions;

• Make sure time is set aside to read a bill before a vote occurs and prevent members from holding votes open long enough to rally enough support for the bill to pass, a tactic used often by Republican Tom DeLay when he was House majority leader;

• Require earmarks disclosures and members to certify that such earmarks do not benefit themselves or their spouses.

While Republicans complained they were being left out of the discussion, Democrats on Wednesday defended their actions.

"Most of the members of the House of Representatives are on record already on practically everything we'd bring up, because this is not a Johnny-come-lately thing," Slaughter said.

FOX News' Jim Mills and Greg Simmons contributed to this report.