Massachusetts Sen. Edward M. Kennedy, the last surviving brother in a political dynasty, has died. He was 77.

One of the most influential senators in history, Kennedy died last night at his home on Cape Cod after a year-long struggle with brain cancer.

In nearly 50 years in the Senate, Kennedy served alongside ten presidents, his assassinated brother John Fitzgerald Kennedy among them. Older brother Joseph was killed during World War II and Robert was felled by an assassin's bullet in 1968.

It fell to Ted Kennedy to deliver the eulogies, to comfort his brothers' widows and to mentor fatherless nieces and nephews.

In the Senate, Kennedy compiled an impressive list of legislative achievements on health care, civil rights, education and more.

There's been praise from Republicans and Democrats, including President Barack Obama, who calls Kennedy "the greatest United States senator of our time."

Obama called Kennedy "a great leader" and praised his work to advance the civil rights, health and economic well-being of all Americans.

He also thanked Kennedy for "his wise counsel in the Senate," as well as his support in last year's presidential race. Kennedy's endorsement in the 2008 Democratic primary was seen as a huge boost to Obama's campaign.

Obama added that as president he benefited from Kennedy's "encouragement and wisdom," even as the senator battled brain cancer.

Massachusetts Gov. Deval Patrick says "one of the Commonwealth's brightest lights" has been extinguished with the death of Kennedy.

The governor, a fellow Democrat, says Kennedy "was a compassionate, effective, visionary statesman," as well as a family man and friend.

Patrick supports changing state law to allow him to appoint an interim successor to Kennedy's seat.

Unlike most states, a successor to a vacant U.S. Senate seat in Massachusetts is chosen by special election five months after the opening, not appointed by the governor.

In a recent letter to lawmakers, Kennedy asked that the law be changed to allow the governor to appoint someone during the course of the election, provided that person pledges not to run for the seat.

In an interview Wednesday on WBUR-FM, Patrick called the proposal "entirely reasonable" and said he would sign the bill if it reached his desk.

Legislative leaders have not said if they support the idea.

Sen. John Kerry says Kennedy was "the best senator, the best advocate you could hope for."

In a statement issued hours after Kennedy's death late Tuesday, Kerry called the late senator an "irrepressible, larger than life presence who was simply the best."

The 2004 Democratic presidential nominee was Kennedy's Massachusetts colleague in the Senate. The pair had grown closer over the years, and moreso as Kennedy battled brain cancer over the past year. Kerry had visited Kennedy at his Hyannis Port home in recent weeks.

Kennedy fought the disease with "grace, courage, and determination," Kerry said.

Sen. Christopher Dodd, perhaps Kennedy's closest friend in the Senate, says Kennedy was a hero to the downtrodden.

The Connecticut Democrat said in a statement Wednesday that Kennedy worked tirelessly on to help erase poverty, civil rights and ensuring justice for all Americans.

"I'm not sure America has ever had a greater senator, but I know for certain that no one has had a greater friend than I and so many others did in Ted Kennedy," said Dodd.

He had visited the ailing Kennedy at his Hyannis Port home this summer to discuss strategy as the Senate worked on a sweeping health care overhaul.

Dodd is in Connecticut recovering from recent prostate cancer surgery.

"I will miss him every day I serve, and every day I live," Dodd added.

Kennedy was often mentioned as a potential Democratic presidential candidate, but the White House is one political prize Kennedy ultimately decided would neither consume nor define his political ambitions.

There was a time when polls showed Kennedy to be more popular among Democrats than the Democratic president: Jimmy Carter.

Kennedy did challenge Carter in the 1980 primaries. But after being unable to clearly answer the question "Why do you want to be president?" in a TV interview, and losing a rules battle at the Democratic National Convention, he laid aside those ambitions.

Later, as his Senate career flourished, he would often say "my ambition is public service, not the constant pursuit of the presidency."

VA Gov. Timothy M. Kaine released a statement upon Kennedy's death.

He wrote, “I am saddened by the news this morning of the passing of a great and gracious statesman. Sen. Kennedy was an undeniable force in the halls of Congress and touched countless lives in his five decades of public service. Like his brothers before him, Sen. Kennedy unfailingly kept the most vulnerable citizens closest to his heart, and I will greatly miss his compassionate voice and remarkable leadership.

“On behalf of the Commonwealth of Virginia, I extend my condolences to his family and loved ones.”

Sen. Mark R. Warner also released a statement.

He wrote, “Sen. Kennedy's death saddens all of us, and my thoughts and prayers are with his family as we mourn this loss. His approach to issues and legislation was respected by all members of the Senate. His legislative accomplishments reflected both his commitment to his principles, and a willingness to cross party lines and find common ground. He brought passion and devotion to the causes he fought for, but always treated his opponents with respect. Sen. Kennedy's approach should be a model for all of us who serve in public life.”

Sen. Jim Webb also released a statement Wednesday.

He wrote, “I have tremendous respect for Sen. Kennedy and the impact he had on our entire congressional body. He was highly regarded on both sides of the aisle. He had a wonderful sense of humor. And he brought great passion to the issues that he pursued. His ability to talk to people of all philosophical persuasions was of great value to our process. I am very fortunate to have been able to spend a few years working alongside him in the U.S. Senate.”