San Antonio is preparing to celebrate its tricentennial, as the city by the river was founded almost 300 years ago in 1718. When officials look through San Antonio’s key dates and moments, consider June 26, 1997:

The day Tim Duncan came to town.

His contribution to San Antonio is 19 seasons with the home team, leading them to five NBA championships.

While No. 21 will be retired by the Spurs on Sunday, it’s a number that lives on through tattoos, flags, truck windshields and in the hearts of San Antonians.

For many locals, Duncan’s impact on the city goes above the 26,496 points, 15,091 rebounds and 3,020 blocks. He helped unite San Antonio in celebration and gave the South Texas city a piece of its identity.

“Yankee Stadium might have the house that Ruth built, but Tim has gone so far beyond that in building up San Antonio,” said Richard Weinhold, a longtime Spurs Season Ticket Member.

San Antonio may be the seventh-largest city in America with 1.5 million people, but it holds onto a small town charm. A spread-out place that can fit 20 Manhattans in the city limits, the diverse demographics can change from one zip code to the next. Without any other major league franchise in the city, the Spurs are its unifying force.

Since 1997, it’s a place where a stoic basketball player from the Virgin Islands could feel at home.

“It’s not New York. It’s not Los Angeles. It’s San Antonio. It’s quiet and laid-back,” said ESPN’s Michelle Beadle, a University of Texas at San Antonio graduate and a former Spurs intern. “You can have your stars and that’s cool. But we were lucky enough to root for a player who lives in a way we’d all want to conduct ourselves. He is unique in the way he’s comfortable in his own skin, and I think San Antonio really got behind that.”

For many in San Antonio, Duncan’s longevity has been the ultimate lesson in loyalty. Duncan had 140 Spurs teammates in his career, including two – Tony Parker and Manu Ginobili – who have been with him for more wins (575) than any other trio in NBA history.

As people around the world began to identify Duncan with San Antonio, the attributes of the city seemed to align with those of No. 21.

The workmanlike attitude. The way actions speak louder than words. The consummate teammate. The persistence. The humility. The class.

“I think the most remarkable thing about Tim is the quality of player he was on the court, and how he wanted to be recognized just as a player,” said Ginobili, Duncan’s teammate for 14 seasons. “There was no ego, there was no chest-thumping, it was about playing and helping teammates. We represented the community that way, and we hear it a lot, that they enjoy not only the buckets and the championships, but how we conducted ourselves and reacted to wins and losses.”

Before Tim Duncan arrived, there wasn’t the same unity in San Antonio. There wasn’t a “Go Spurs Go” chant yet.

Although the Spurs reached the playoffs in 20 of 24 seasons before Duncan’s arrival, the franchise had never reached an NBA Finals, losing in the conference finals four times.

In Duncan’s second season, the Spurs won the 1999 NBA Championship.

For the first time, Tim Duncan helped make San Antonio feel like the center of the universe.

“I remember how traffic shut down on every road leading into downtown in 1999,” said Ben Olivo, a lifelong San Antonian who runs The Tacoist, a site chronicling local tacos. “It didn’t matter which part of town you were coming from. The only time I could think of in our city’s history where everybody converged downtown like that might have been when World War II ended? That’s crazy, but that’s what Tim and the Spurs have given this city.”

The celebrations repeated in 2003, 2005, 2007 and 2014. At the same time, the NBA was gaining hundreds of millions of fans worldwide.

Duncan’s career began in the age of dial-up internet. As technology changed, the global reach of the NBA grew exponentially, giving people from Argentina to the Philippines their first view of San Antonio stitched on the front of a jersey.

Bexar County Judge Nelson Wolff said Duncan and the Spurs’ success helped give San Antonio worldwide recognition. Wolff said the county recently had a delegation from Japan in town, and there was no language barrier when the Spurs were the topic of conversation.

“He’s put San Antonio on the world map,” Wolff said. “There’s not a place you can go in the world now and not know about the San Antonio Spurs. Ever since Tim Duncan got to San Antonio, people identify us more with the Spurs than they do with the Alamo.”

San Antonio Mayor Ivy Taylor added, "He taught us how to work hard, win and be humble. He truly fits the definition of champion."

It’s a sentiment echoed by those whose jobs took them to Washington D.C.

“Tim Duncan is pure class,” said U.S. Housing and Urban Development Secretary Julian Castro, a former San Antonio mayor. “As a player and as a man, he embodies the best of our city — talented, hardworking, humble and a winner. San Antonio couldn’t have asked for a better ambassador than Timmy.”

One subject where politicians on both sides of the aisle agree is the impact Duncan had on San Antonio.

“Tim is more than just one of the most accomplished players in NBA history, he is the definition of a humble hero who delivered for San Antonio on – and off – the court,” said Republican U.S. Senator John Cornyn, a San Antonio native.

Back in South Texas, Bill Tindol purchased his season tickets the day after the 1997 Draft Lottery, when the Spurs landed the No. 1 overall pick that would be used to select Duncan. A resident of Uvalde, a town 90 miles away from the AT&T Center, Tindol has made the 180-mile round trip for 20 seasons thanks to Duncan. A lot of the dunks and blocks run together in his memory, but the lasting impressions for Tindol are Duncan’s competitiveness and the player-coach relationship with Gregg Popovich.

“It’s like losing an old friend not to see him out there,” Tindol said. “You just always expected him to be back even though everybody moves on. He has been the model citizen and player. He’s the human being that any of us would aim to be.”

Naomi Gutierrez is reminded of Duncan’s values every time she looks at her right forearm. She showed her appreciation for Duncan with ink, getting a tattoo of him. The tattoo, done by local artist Chris Romo, depicts Duncan hugging a ball from elbow to her wrist.

“When I look at my arm, it’s a reminder of where I’m from and how proud I am of my city,” Gutierrez said. “I think Tim is the greatest, and he’s always been a role model for San Antonians. I can see my arm, think of his hard work and sacrifice and be inspired.”

Jon Paul Dennison met his wife at the AT&T Center. When it came time to name their first children, twin boys, they named them Duncan and Parker.

“I’ve appreciated watching Tim for my entire adult life,” said Dennison, who also has a son named Elliott. “So many of our favorite memories are tied into the Spurs.”

There are San Antonians in college experiencing their first season without Duncan. They’ve only known a world of bank shots, tough defense and the fundamentals that make an unassuming superstar. An entire generation of San Antonians has had a father or mother or grandfather or abuela explain why they should take note of the way Tim Duncan conducts himself.

Mariachi singer Sebastien de la Cruz is now a freshman in high school. Three years ago, his Star-Spangled Banner at Game 3 of the 2013 NBA Finals drew racist remarks and became national news. In a moment that exemplified San Antonio, Cruz brushed off the comments and returned for the Game 4 anthem with the city and the Spurs rallying behind him.

Under the sudden spotlight, de la Cruz said he thought about what his role model might do in the same situation.

“I learned a lot from Tim Duncan,” de la Cruz said. “He showed me that all you have to do is let your actions speak louder than your words. Watching Tim Duncan taught me how respect is earned. That’s what he taught all of us, and I want to thank Tim for making me who I am today.”

lchan@attcenter.com