On Jan. 11 in Arizona, with a 45-40 win over Clemson, Alabama raised a question that doesn't get to be asked often: Is this coach the greatest in the history of his sport?

Nick Saban has certainly made his case, although it's a case that is not yet closed for the 64-year-old, who's getting ready for another season at the helm of the Crimson Tide. Saban has won five national championships in his last 12 seasons as a college coach, with eight straight top-10 finishes. It's one of the greatest runs in college football history, giving Saban an argument in the debate about the sport's best-ever coach.

We decided to expand the question. Last summer, Sports on Earth broke down the 100 best teams in college football history, according to Sports-Reference's Simple Rating System data.

Now, we have taken a more subjective look at the 100 greatest coaches in college football history, publishing our list in four installments of 25 from July 25-28. All of the parts, plus three related articles, are featured below.

Criteria for the countdown are loose. It is difficult to compare eras and circumstances and longevity vs. peaks, and there are many definitions of coaching greatness. In our case, we're trying to strike a balance when determining which coaches -- throughout the entire history of the sport -- were the most impressive winners and made the biggest impact on college football on the field. Among other things, we've taken into account wins, winning percentage, national championships, AP poll finishes, postseason appearances, influence on strategy, staying power, Sports-Reference's SRS and coaching context (comparing accomplishments to other coaches at a school or schools with similar profiles).

There are a few restrictions on eligibility: We're including major college football coaches only (which excludes greats like Eddie Robinson and John Gagliardi), and for those who have experience at multiple levels of college football, we're almost exclusively considering accomplishments at the FBS or major college level (for this reason, coaches like Chris Ault and Brian Kelly miss the cut, although Kelly could join the list soon if his success at Notre Dame continues). Also, to be considered, candidates must have at least eight years of head coaching experience (which excludes Jimbo Fisher and Chip Kelly … at least for now).

College football will celebrate its 150th anniversary in three years, meaning there is a long, long list of possible candidates. One-hundred is a nice round number, but it's still an arbitrary one, and thus many deserving coaches had to be left out. It's easy to narrow down the clear all-time greatest coaches, but debates about the much longer list of very good coaches could go around in circles forever. This is our attempt to sort it out.

Part I: 100-76

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Our countdown of the 100 greatest coaches in college football history begins with a mix of program builders, a few champions and coaches who had long, mostly successful tenures without winning national championships.

Part II: 75-51

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The countdown moves on with some of the toughest coaches to place on the entire list. That includes the three most prominent figures of The U -- Howard Schnellenberger, Jimmy Johnson and Dennis Erickson -- and three excellent coaches who practically built their programs from scratch -- Bill Snyder, Frank Beamer and Barry Alvarez.

Part III: 50-26

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Most coaches who made the top-50 cut are national champions, with a few exceptions. From recent coaches with short but fantastic bursts of major-college success, like Pete Carroll and Jim Tressel, to throwbacks who may be forgotten, like Charley Moran and George Woodruff, Part III covers a wide range of college football characters.

Part IV: 25-1

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The best of the best. These are the most legendary coaches that major college football has ever produced, from Walter Camp, Fielding Yost and Amos Alonzo Stagg at the beginning to Nick Saban and Urban Meyer now, with Bear Bryant and others in between.

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Saban vs. Bear: The Battle for Bama

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It once seemed unthinkable for anybody to compare to Bear Bryant, but Nick Saban has made a legitimate argument to being not only the best Alabama coach, but the best college football coach period. How do the two measure up against each other?

Top 100 Coaches: Future Candidates

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Our ranking of the top 100 college football coaches ever included 10 active college head coaches, with a handful of others on the cusp. So which current coaches have a chance to make future revised lists? Here are 10 attempting to build on their strong resumes and make a move toward the top 100.

Bill Snyder Is Not Slowing Down

By David Ubben

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In 1989, Bill Snyder took on one of the biggest challenges in college football: a moribund Kansas State team with little track record of success, coming off two winless seasons. Snyder has succeeded more than anyone could have imagined, and at 76, he's still going.