William J. Baker had to retire to finish the book about sports and religion that he started 20 years ago.

“Playing with God: Religion and Modern Sport” is the retired professor’s opus. It was published earlier this year by Harvard University Press, two years from when he retired after teaching at the University of Maine for nearly three decades.

“I wanted to write a book directly related to my experiences,” Baker said recently. “The two great experiences of my youth were the Baptist religion and sports. This book is essentially a summation of all the scholarship I’ve ever done and of my life.”

Sports and religion dominated the north Georgia textile mill town where Baker, 68, of Tremont grew up. He played baseball, basketball and football, took part in youth evangelism and dreamed of becoming a Baptist preacher.

His career goals changed while an undergraduate on a football scholarship at the Furman University in Greenville, S.C. He went on to earn a second bachelor’s degree in divinity at Southeastern Seminary at Wake Forest University, Winston-Salem, N.C., and earned his doctorate in history from Cambridge University in Cambridge, England.

Baker is now an Episcopalian. He said that the Baptist denomination was too structured for him and his wife, Christina Baker, a retired English teacher from University College Bangor and a former state representative for Bangor.

During his years at the university, Baker taught classes on the history of sport. His biography of Jesse Owens made a splash on the publishing scene in 1986 and was reissued in paperback last year. But the “big book” on sports and religion tugged at his psyche and the more research he did, the more he understood how intertwined the two had become.

“For all their differences,” Baker wrote in his introduction to the book, “religion and sport seem to have been made in the image of each other. Both are bathed in myth and sustained by ritual; both reward faith and patience; both thrive on passion tempered with discipline.”

Baker’s book traces how sport and religion, inseparable during the Greek Olympic games, parted company during the Protestant Reformation only to resurface 400 years later as a tightly woven cloth interlaced with threads of patriotism. Nowhere has that transformation been more dramatic than in North America and Western Europe, according to Baker.

The Industrial Revolution changed the way Americans worked and played. At the forefront of that change was the Rev. Henry Ward Beecher, pastor of Plymouth Church in Brooklyn, N.Y., for 40 years. In his early sermons, Beecher “railed against idleness, gambling, prostitution, intemperance, theaters, circuses, horse races, and various other popular forms of amusement,” Baker wrote.

By the 1850s, Beecher, whose sister Harriet Beecher Stowe wrote “Uncle Tom’s Cabin,” tempered his views and recommended muscular games and exercises for New York City’s youths. He was one of the first American clergyman to advocate the theory of “muscular Christianity,” a term imported from Victorian England, according to Baker.

“Muscular Christianity originated,” he wrote, “in the fervent belief that physical exercise and competitive games made for better digestion, lungs, and muscles, and that a stronger body would fortify the human spirit against the beguiling allurements of big-city life. … Competitive sport became a substitute for the rigors of physical labor, frontier dangers, and warfare, the customary measures of manhood. For much of modern history, males have dominated athletic clubs and sporting events because men have had the most to win in terms of self-respect and purpose.”

The Young Men’s Christian Association, along with facilities for women, grew out of the muscular Christianity movement in the late 19th century. In cities with large Jewish populations, similar organizations were formed. A comparable sentiment led to the creation of community centers, playgrounds and municipal parks and recreation departments. Catholics joined in during the Depression era with the creation of Catholic Youth Organizations.

“What surprised me was the expanse across denominational lines,” Baker said in response to a reporter’s question. “The attempt by Jews, Catholics, Muslims and Protestants to correlate sport with religious principal was surprising. Each one collates it differently – very differently. I was especially surprised by the richness of their art of reasoning on sport.”

Baker traveled extensively over the years to research the book. He interviewed Catholic theologians and Knute Rockne historians at Notre Dame University in South Bend, Ind., and culled the national archives of the YMCA in St. Paul, Minn. He went to Liberty University in Lynchburg, Va., the college founded by the late Rev. Jerry Falwell that used sports as a way to save souls and convert the unchurched.

“Sport has been used by religion to make it more palatable to youth,” Baker said, “and sport is using religion to pray down the power of God.”

The author does not see sport and religion going their separate ways anytime soon.

“I see sport going highly commercial toward growth in classic capitalistic terms,” Baker said. “American religion is doing the same thing – growing Congregations under a commercial banner.”