Former Congressman William H. Gray III, a giant in Philadelphia politics who mentored a generation of African American leaders, died Monday in London, according to his office in Washington, D.C. He was 71.

No cause of death was immediately available.

Family spokesman Bill Epstein said Rev. Gray was attending the tennis matches at Wimbledon with his youngest son, Andrew. "Apparently, it was a sudden death," said Epstein, who served as press secretary when Rev. Gray was elected to Congress.

In Harrisburg, the House stood and paused in a moment of silence. Friends struggled to grasp the news that he was gone - to them he seemed strong, an avid tennis player. Others who knew Rev. Gray for decades - colleagues, political allies and church members - recalled him as a respected Philadelphia pastor, a visionary congressman, a fighter for justice and a man of keen political sense who put his charisma to good use.

"He could walk down the hallway, and everybody knew him, he knew everyone," said Congressman Bob Brady. "I'm absolutely positively shocked. It's a major, major loss to the city, to the area and to the nation."

Mayor Nutter described himself as "stunned, saddened and hurt," by the death of Rev. Gray, whom he called "a transformative leader among leaders."

"He knew guys on the corner, and he knew Nelson Mandela and everyone in between," Nutter said. "In the chess match of politics, he knew how to get things done."

At the time of his death, Rev. Gray was chairman emeritus of Gray Global Advisors, a business and government consultancy based in Washington. Prior to founding the firm, he was president and CEO of the United Negro College Fund, for which he raised over $2.3 billion for minority institutions.

His spiritual home was the pulpit of Bright Hope Baptist Church in North Philadelphia, one of Philadelphia's elite black churches. In 1972, Rev. Gray succeeded his father, who had succeeded his own father, as pastor.

His oration? "Short, sweet, to the point. He left you feeling good," said a friend and ally, Philadelphia City Councilwoman Marian Tasco.

Rev. Gray stayed as pastor while he served in Congress, from 1979 to 1991, commuting from his home in the northern Virginia suburbs to preach on Sundays.

"If you look back over the last 50 years, there's a handful of people that stood out as transformative leaders in Philadelphia, and Bill Gray is one of them," said George Burrell, a former city councilman and longtime political ally.

Burrell counted Rev. Gray as one of his two or three closest friends. Their children grew up together. They played tennis on a regular basis.

Rev. Gray represented the Second Congressional District of Pennsylvania and rose to become Majority Whip of the House of Representatives, the first African American in the 20th century to assume that post. He also served as chairman of the Budget Committee, and as a member of the House Appropriations Subcommittee on Transportation and Foreign Operations.

"He was a trailblazer. He was a pioneer," said state Rep. Dwight Evans, who considered Rev. Gray a mentor. "I learned a lot from him about building relationships with rural legislators."

In Congress, Rev. Gray helped shape the direction of U.S. foreign policy and pushed government resources towards international aid and development.

"I think he could have been speaker of the House if he had stayed in," said Peter Vaira, a former U.S. Attorney and longtime friend. "Everybody - no matter which side you were on - could work with him."

In 1991, Rev. Gray surprised political watchers by leaving Congress to lead the college fund. He continued to run the church as pastor.

His influence in Philadelphia - and on Philadelphia - was enormous, his work for social justice relentless.

"It's a tightrope to be both a leader of a major spiritual community church and also to be a major political leader, probably the number one political leader, and I think he walked it well," said retired Inquirer reporter Acel Moore, who knew Rev. Gray.

Former Gov. Ed Rendell said Rev. Gray's combined roles as political and spiritual leader "made him an incredibly dominant factor in Philadelphia.

"He used both of those positions to help people, to make lives better, to create opportunity for people who had none, and to make sure that the most vulnerable citizens were protected."

Rev. William B. Moore said he felt numb Monday night after hearing the news. The two men met in 1974 in Philadelphia, and Moore worked for his friend in Congress. Moore would fill in at Bright Hope when Rev. Gray was not available.

"He loved helping people," Moore said. "He loved helping the city."

Rev. Gray would say he was a politician but then add, "First and foremost, I am a Baptist preacher," Moore said.

City Councilwoman Tasco worked as Rev. Gray's campaign manager in 1977 and 1978, and went on to work as his director of constituent services in Philadelphia when he was in Congress.

She was still trying to accept the news on Monday. "He's just not somebody I would expect not to be here," Tasco said.

Rev. Gray was always there, said Bill Miller IV, whose 50th Ward organization in Northwest Philadelphia helped elect him Congress and remained closely allied over decades. Rev. Gray was so attentive to detail that even as the U.S. House majority whip, he would call his people in Philadelphia in the middle of the night to talk strategy in elections.

"He rose to the highest level of Congress, and yet he would still call you about ward and division politics," said Miller, a public-relations executive and veteran political consultant. He and his wife Linda, the former ward chair, were at Tasco's house Monday evening, sharing memories.

They recalled how Rev. Gray and his allies would strategize, always over lunch, all over the place - Holmes' Restaurant in Camden, Susanna Foo in Center City, Tobin's in West Oak Lane - where he would play Pac-Man between feasting on fried chicken and fish. Rev. Gray loved Pac-Man so much he bought a real arcade version of the game for his house.

Tasco said Rev. Gray discussed his health during a conversation last week. He told her he was following his doctor's orders "because I want to be here a long time and enjoy my grandchildren," she recalled.

Instead, on Monday, friends began assessing his place in history.

"I think Bill Gray was the most significant African American political figure in Philadelphia in the past 35 years," former Mayor Wilson Goode said. "His accomplishments as a Congressmen, as budget chair and majority whip put Philadelphia on the map."

Goode rattled off names - Burrell, Tasco, Evans, Bishop, Chaka Fattah. "There is a whole list of people who got elected because Congressman Gray supported them."

Rep. Louise Bishop (D., Phila.) said, "I wouldn't be here today if it wasn't for him," because he supported women in politics.

"There is void," she said. "Congressman Gray has been called to another assignment."

Political life can be turbulent. In 1991, federal authorities sought evidence in a criminal investigation that focused on Rev. Gray's finances, according to Inquirer accounts at the time. No charges were ever filed. Vaira, who served as Rev. Gray's attorney, dismissed the inquiry as "purely political."

In 2004, after spending half his life as pastor of Bright Hope, Rev. Gray decided to step down, ending three generations of successive family leadership.

"We've had five pastors - and three of them were named William H. Gray," friend and church member Augusta Clark said then.

Rev. Gray took over at Bright Hope after the death of his father, William H. Gray Jr., and the plan was for him to be succeeded by Rev. Cean James, the church's executive pastor.

But in 2005 the church was jarred by two revelations and Rev. Gray was besieged with questions: Why did Bright Hope fail to detect false academic claims made by the young preacher who was designated to succeed Rev. Gray? And why did the church allow a choir director accused of sexual offenses with underage girls to remain in his job?

Rev. Gray was forced to cancel his plan to retire from the church, even though he had already begun a new job as a consultant at a major law firm in Washington.

Bright Hope was stunned by the news that Rev. James, the assistant minister who was to become senior pastor, had faked his credentials. James resigned. And Rev. Gray acknowledged a failure of due diligence in not more closely checking James' background.

"Nobody is more heartbroken about this than me," Rev. Gray said in an interview. "I blame myself."

About the same time, Otis Joseph, then a 28-year-old choir director at Bright Hope, went on trial on charges of raping two underage girls who were once his music students at Germantown Settlement Charter School.

Rev. Gray said the church permitted Joseph, free on bail, to continue leading the church's adult choir while the criminal cases were pending. He said the church viewed him as "innocent until proven guilty."

Joseph was later convicted and sentenced to at least 33 years in prison.

On a freezing day in February 2007, Rev. Gray gave his farewell sermon at Bright Hope. Hundreds of parishioners and guests braved the cold and jostled for pew space.

Standing on the same pulpit from which the Rev. Dr. Martin Luther King Jr. once preached, the then 65-year-old former congressman read a verse from Joshua. He used the transfer in leadership of the Israelites from Moses to Joshua as a metaphor for the passing of church leadership to Kevin Johnson, a former assistant minister at Abyssinian Baptist Church in Harlem.

"We must grow and evolve into what God intended us to become," Rev. Gray shouted, his arms reaching toward the often cheering crowd. "Our new Joshua is well-trained and filled with the holy spirit."