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DENVER -- **It began with Marvin Harrison. Where it ends, no one yet knows.

But with his 7-yard scoring toss to tight end Julius Thomas Sunday, Peyton Manning became the second player in NFL history with 500 touchdown passes, and hit the milestone in 243 games, 49 fewer than Brett Favre needed.

With his first NFL offensive coordinator (Tom Moore) and position coach (Bruce Arians) looking on from the Arizona sideline, Manning threw a perfect strike to Thomas for the score that put the Broncos in front for good en route to a 41-20 win.

"It's interesting, two coaches on Arizona's sideline were both there my first game when I threw my first touchdown," said Manning. "I give both of those men a lot of credit for helping me improve as a quarterback. I do think about how many people have helped me throughout my career from something like that and I was thinking about how grateful I am for that help and support."

Thomas broke outside Cardinals safety Tony Jefferson near the goal line. That created all the separation Manning needed to hit the milestone and put the Broncos in front 10:17 into the game.

"It was a good call," said Thomas. "I kind of had outside leverage a little bit, needed to go outside. I tried to hold him inside a little bit, gave him a little move at the top of the route. Broke it off, kind of got surprised a little bit by the ball."

Surprised, perhaps -- but not to the point where he couldn't make the play. Plays like that give Thomas a celebrated place among the pantheon of targets upon whom Manning has leaned.

Help in reaching the milestone comes from all around, including targets like Thomas, and the Broncos' three starting wide receivers: Demaryius Thomas, Wes Welker and Emmanuel Sanders. Demaryius Thomas broke a 12-year-old Broncos record by amassing 226 receiving yards, and Manning walked away from Sunday with a personal-best 479 yards, the second-highest single total in Broncos history.

The 500th pass raises the possibility of more milestones in the future. Manning threw three more touchdown passes, pushing his total to 503, just five behind Favre's record. At Manning's pace in his years as a Bronco, he could hit that mark in the next two weeks.

Favre's passing yardage record of 71,838 could be approached late next season. The same is true of Favre's completion standard of 6,300.

Manning's 500th touchdown was a celebration of everything in the past of a brilliant career that helped redefine the statistical standards and study habits of the sport's signature position.

The quarterback's accomplishments have earned him the right to wax nostalgic about the past. That's what he did last month, as he sifted through the folders of his hard-drive mind to recall some targets who caught a single touchdown pass. A guy named Trevor Insley, he caught one, Of course Mitch Unrein would be in that category. There was a tight end named Mike Roberg in there. [Also] Tom Santi and Lamont Warren," recited Manning.

It's one thing to remember the one-off targets; another he cited was Gijon Robinson. It's another to recall the details.

"The scary thing is I can actually remember the touchdown. Gijon Robinson caught a goal-line naked against New England in New England." Manning said of the second-quarter score in a Nov. 21, 2010 game at Gillette Stadium. "Fake bootleg left, roll right, wide open because nobody thought we would be throwing it to Gijon Robinson.

"I can't remember a lot of things -- important things -- but I have a lot of useless information in my mind. I can remember Trevor Insley caught a pass up the left sideline against Atlanta on a fake screen pass," Manning said of the 19-yard connection on Dec. 16, 2001.

"That's actually very disturbing memory."

It won't be disturbing that he will someday recall No. 500 with such clarity. To throw so many touchdown passes so soon is to create a standard to which quarterbacks will aspire now and for the foreseeable future.

And the final standards are to be determined. This isn't an endpoint; it's a way station. And by jogging back to the sideline after a brief pause to acknowledge the moment, he underscored that fact.

"Peyton really didn't have a reaction," said Sanders. "He went right back to the sideline, got into the playbook in terms of looking what we can do to improve to continuously score points."

There is more to do, and more to come. The 500th touchdown is a plot point in the novel of Manning, with the final chapter and epilogue still off in the future.