Shortly before the 2000 presidential election, C-SPAN commissioned artist Chas Fagan to create 41 oil portraits, one for each of the men who, at that point, had ever been elected president.

Fagan had just three months to create the pieces, which were to be used in the production of C-SPAN’s “American Presidents: Life Portraits,” a 41-part series that told the life story of each commander in chief.

Ultimately, Fagan finished in time, and the series went on to score high ratings and even win a Peabody. But the portraits ended up having an even longer-lasting impact than the show.

C-SPAN put the pieces in a museum-quality collection and sent them on tour, visiting presidential libraries, political conventions and even the White House. When George W. Bush was elected president, Fagan created a portrait of him.

Now, just in time for the 44th president’s inauguration, C-SPAN has brought the portraits to Union Station, displaying them with a new addition: Fagan’s newly painted portrait of President-elect Barack Obama.

“They’ve taken on a life of their own, but I think deservedly, just because of their subject matter,” Fagan said of the portraits. “We actually haven’t had that many presidents. When you add them up, there really aren’t that many.”

“American Presidents: Life Portraits” is the only collection that features oil paintings of each president painted by the same artist. It’s the fourth time the exhibit will be on display in Union Station, the third for a presidential inauguration, and C-SPAN estimates that since it was commissioned in 1999, more than 11 million people have seen the exhibit.

Its success is a joy for Fagan, who also painted former first lady Barbara Bush’s official White House portrait, and a portrait of former Speaker Tom Foley (D-Wash.), which now hangs in the House Agriculture Committee hearing room.

The artist called the presidential portrait collection the most unique he’s ever put together. After all, Fagan normally has plenty of time to study a person before getting started on a piece.

In this case, it wasn’t just a time crunch that proved challenging. Some of his subjects had been dead for nearly two centuries, leaving only other painted portraits as a reference.

“The hope was to create something that was more original,” Fagan said. “I just went through every single image of every portrait available that I could find.”

The easiest subjects were presidents who had been photographed when photography was brand new — the lighting of that time captured the shape and texture of their subjects well, Fagan said.

Modern presidents actually proved difficult — candid photos often capture a person making a strange, contorted face, for example. And cheesy, full-fledged smile pictures aren’t exactly a window to the soul.

“Trying to find a relaxed, subdued image of the president-elect was hard, so the result of what you see there is not based on a single photograph,” Fagan said. “These are not normal portraits.”

Normality aside, the exhibit — which is being co-sponsored by the White House Historical Association — is quite educational. Along with the portraits themselves, the exhibit includes photographs, newspaper clippings and biographical information, along with 18 audio recordings of modern presidents.

Fagan’s favorite pieces are of Presidents Abraham Lincoln and Theodore Roosevelt, especially Roosevelt. The rough rider’s features really match his famed energetic, rambunctious personality, Fagan said.

And for the artist, the portraits’ continued fame continue to bring pride.

“Initially it was just for television, just television images that they could use for their weekly shows on each president,” Fagan said of his collection. “And it just grew. … Since the White House Historical Association jumped in, too, it’s made it much more interesting.”

Fagan said he hasn’t seen the latest display with Obama’s portrait, but he hopes to visit Washington, D.C., from his base in North Carolina sometime this week to see it. If he doesn’t, however, he is still likely to get feedback.

“I get phone calls at my house, at my studio, from across the country, every week,” Fagan said. “People either having seen it and inquiring, or people inquiring trying to get a copy.”

“American Presidents: Life Portraits” runs through Sunday at Union Station.