We’re going to start in 1905, a season that saw at least 18 college football players die.

"Football developed into this slugfest – and it really was a slugfest along the line of scrimmage," says sports historian Ronald A. Smith.

By 1905, football had already outlawed the sport’s most dangerous play, the flying wedge. But the game found other ways to kill its players. Smith says the most popular play called for the offense to simply smash into the defensive line and hope for the best. Beyond that, fighting was most definitely tolerated, if not allowed.

"At one time, you wouldn’t be booted out of the game unless you were called for three slugs," Smith says. "It was a brutal game."

Brutal enough to bring calls for the abolition of football, which got the attention of one football-loving resident of 1600 Pennsylvania Ave.

"The President of the United States, Teddy Roosevelt, got involved. He called Harvard, Yale and Princeton down to the White House to discuss the unethical play that was going on and the brutality that was going on," Smith says.

"The President discussed the question of foot ball in general and made a few remarks on unfair play," Harvard head coach Bill Reid wrote in his 1905 diary.

Ron Smith discovered Reid’s 440-page typewritten diary in the archives at Harvard and published it in a book called "Big-Time Football at Harvard, 1905" back in 1994.

"Mr. Roosevelt ... wanted to see if there was not some way in which the feeling between the colleges could be improved," Reid wrote.

But football wouldn’t change — at least not yet. And when change finally came the following year, Coach Reid would be instrumental.

A Hero Returns To Harvard

As a Harvard sophomore back in 1898, Bill Reid scored two touchdowns against Yale. And then as a coach in 1901, he led Harvard to its first undefeated season. Reid went back home to California for a while, but in 1905, after Harvard failed to score a single touchdown in three years, Reid returned to Cambridge as the school’s one true hope.

Harvard Football coach Bill Reid in 1901. (Harvard University Archives)

"And he wrote this diary principally so that he and future coaches could know better how to beat Yale. That’s the only important game," Smith explains.

In order to beat Yale, Harvard would need to keep its players healthy through the last game of the season.

"Dr. Nichols will be medical advisor for the eleven, and is going to be a mighty valuable man there. Already he has made a quantity of first rate suggestions," Reid wrote in his diary.

And soon, the Harvard football team would get some medical advice that was 100 years ahead of its time.

Unexpected Discovery

It’s that advice that caught the eye of another former Harvard football player, Christopher Nowinski. The year was 2005, a whole century after Bill Reid wrote his diary, and Nowinski was in the middle of writing a book about sports and concussions. Dr. Bennet Omalu had only recently published his discovery of CTE in the brain of a deceased football player. Research was just getting started, so Nowinski didn’t have nearly as much to work with as he does today.

"My roommate was a former teammate of mine and he was a big Harvard football memorabilia buff. And he just happened to mention to me, ‘You know, you should check out that book to see what they thought about concussions back in 1905,'" Nowinski recalls. "And I told him, ‘You idiot, they didn’t talk about concussions back in 1905. I’m not going to find anything.’ But I was shocked to find that they talked about concussions throughout the book."

And then there was this: A speech given to the Harvard football team by Dr. Nichols. Here’s how Coach Reid remembered it.

"The next thing he said was that in case any man in any game got hurt by a hit on the head so that he did not realize what he was doing, his team mate should at once insist that time be called and that a doctor come onto the field to see what is the trouble."

Nowinski couldn’t believe what he was reading. After playing football at Harvard, he had become a pro wrestler. He suffered so many concussions that doctors told him he had permanent brain damage. He's at risk for developing CTE.

"And I thought, 'Wow, the team doctor gave a speech to the team that says, "Call a time out if you think your teammate has a concussion?"' I said, 'That’s weird, because I don’t remember ever getting that speech.'"

"I vividly remember in high school having teammates in the huddle that could not remember the plays, and it just never, never crossed my mind that that was a bad thing – that that wasn’t anything but a normal part of playing football.