On Jan. 29, 1839, in the little chapel in the English village of Maer, a religious, 30-year-old woman named Emma Wedgwood put on a green silk dress and got married. She believed firmly in a heaven and a hell. And she believed you had to accept God to go to heaven. She married Charles Darwin.

As we head into a new era for a country that has struggled for too long with the marriage of science and religion, we should take a look at the marriage of Charles and Emma Darwin.

When Charles came home in 1836 from his five-year voyage around the world, which included the visit to the Galapagos Islands, he was already seeing life and creation in a new way. And as he courted Emma, he also was secretly scribbling notes about a new idea, his theory of evolution, in leather-bound notebooks marked "private."

He knew that his view of creation would rock the faith of Emma and almost everyone in England, and as he prepared to propose to her, he agonized. Charles' father advised him to keep his mouth shut. "Conceal your doubts," he warned.

But Charles couldn't do that. He was too honest. He told Emma of his doubts about the veracity of the Bible and of his growing skepticism about religion.

Emma said she would marry him anyway. She prized his candor, and she knew he was a good and moral man. But in a letter she sent him soon after their engagement, she told him that she was sad that "our opinions on the most important subject should differ widely."

This was the first of several letters about religion that Emma wrote to Charles during their lives. She urged him not to close the door on faith. And she shared her fears that they would be separated for eternity. Charles always listened to what she had to say, and they talked about the problem. He kept each letter close. He wrote on one of them, "When I am dead, know that many times, I have kissed and cryed over this. C.D." On another he wrote, simply, "God bless you."

Charles and Emma had 10 children together. Three of the children died; the death of their beloved 10-year-old daughter, Annie, broke their hearts. That loss could have driven them apart forever. It strengthened Emma's faith and all but closed the door on God for Charles. But they fought for their marriage. The day after Annie died, Emma wrote to Charles, "You must remember that you are my prime treasure (and always have been)."

Darwin worked for decades on his theory. He tried to make his argument as strong and solid as possible, and he also aimed not to offend. He showed Emma drafts, and he worked harder on a passage when she wrote in the margin, "a great assumption." In 1859, as he finally readied "The Origin of Species" for publication, he gave the manuscript to Emma. She was always his best and most trusted editor. As she read the argument that essentially took God out of creation, she did not ask Charles to soften it at all. In fact, she helped him strengthen his book by making the language clearer. (She also cleaned up his spelling and punctuation.)

Through the years, the two continued to talk and listen to each other about this "most important subject," as Emma called it. She encouraged him not to approach religion in the same way he approached science. What leads to faith, she said, is "feeling, not reasoning."

After he became famous, people often wrote to the sage of Down House and asked him what he believed about God. Usually Darwin demurred. And he echoed Emma. He said his views were of "no consequence to anyone except myself" and that the question of religion was for theologians, not for scientists. Still, he often pointed to his friend, the American botanist Asa Gray, who was both an evolutionist and a theist.

Charles and Emma were married for 43 years. In his last years, Charles renewed a fascination with worms and wrote "The Formation of Vegetable Mold through the Action of Worms with Observations on Their Habits," a bestseller in its day. Emma, never much interested in science, found herself joining him in his obsession. They spent hours together watching the worms in the garden of Down House, side by side.

Although they never were able to see eye-to-eye on the question of religion and God, they were able to reach their hands across the gulf. In the end, each of them accepted and, it seems, truly understood what the other believed.

If it is a sign of intelligence to be able to hold two opposite thoughts or opinions in your head, then it is a mark of a successful marriage to be able to truly see the other person's point of view. This is also the mark of a successful society.

There is an apocryphal story that Darwin accepted God on his deathbed. The true story is this: When he suffered his last and fatal heart attack, Charles told Emma that he was "not the least afraid of death." And as he slipped away, he told her, "Remember what a good wife you have been to me." Emma held Charles in her arms as he died.

Deborah Heiligman is the author, most recently, of "Charles and Emma: The Darwins' Leap of Faith."