Golf legend Arnold Palmer died Sunday afternoon in Pittsburgh of complications from heart problems. He was 87.

Beyond his golf, Palmer was a pioneer in sports marketing, paving the way for scores of other athletes to reap in millions from endorsements. Some four decades after his last PGA Tour win, he ranked among the highest-earners in golf.

"Thanks Arnold for your friendship, counsel and a lot of laughs," Tiger Woods tweeted Sunday night. "Your philanthropy and humility are part of your legend. It's hard to imagine golf without you or anyone more important to the game than the King."

On the golf course, Palmer was an icon not for how often he won, but the way he did it.

He would hitch up his pants, drop a cigarette and attack the flags. With powerful hands wrapped around the golf club, Palmer would slash at the ball with all of his might, then twist that muscular neck and squint to see where it went.

"When he hits the ball, the earth shakes," Gene Littler once said.

Palmer was part of golf's "Big Three," with Jack Nicklaus and Gary Player. His last PGA Tour title came in the 1973 Bob Hope Desert Classic. He won four times at the Masters, twice at the British Open and had one victory at the U.S. Open. The only major to elude him was the PGA Championship, where he was runner-up three times. He finished second in the U.S. Open four times and was inducted into theWorld Golf Hall of Fame in 1974.

The USGA tweeted that "we are deeply saddened" by Palmer's death, calling him "golf's greatest ambassador."

"I'm pleased that I was able to do what I did from a golfing standpoint," Palmer said in 2008, two years after he played in his last official tournament. "I would like to think that I left them more than just that."

"Arnie's Army," began at Augusta National with a small group of soldiers from nearby Fort Hood, and grew to include a legion of fans from every corner of the globe.

Palmer stopped playing the Masters in 2004 and hit the ceremonial tee shot every year until 2016, when age began to take a toll and he struggled with his balance.

But then, the standard he set went beyond trophies. It was the way he treated people, looking everyone in the eye with a smile and a wink. He signed every autograph, making sure it was legible. He made every fan feel like an old friend.

Palmer never like being referred to as "The King," but the name stuck.

Nicklaus tweeted that he was "shocked to hear that we lost a great friend."

Palmer was equally successful off with golf course design, a wine collection, and apparel that included his famous logo of an umbrella. He bought the Bay Hill Club & Lodge upon making his winter home in Orlando, Florida, and in 2007 the PGA Tour changed the name of the tournament to the Arnold Palmer Invitational.

Tom Callahan once described the difference between Nicklaus and Palmer this way: It's as though God said to Nicklaus, "You will have skills like no other," then whispered to Palmer, "But they will love you more."

Only four other players won more PGA Tour events than Palmer — Sam Snead, Nicklaus and Woods.

Palmer's first wife, Winnie, died in 1999. They had two daughters, and his grandson Sam Saunders plays on the PGA Tour. Palmer married Kathleen (Kit) Gawthrop in 2005.

Information from The Associated Press was used in this report.