From what I can tell, Mark Twain was not a Christian, nor did he claim to be when he began courting Olivia Langdon. Back in Twain's day, a man typically had to get permission from a woman's parents before marrying her. Mark Twain had a problem, however. Olivia Langdon came from a professing Christian family that would not allow their daughter to marry an unbeliever. To overcome this obstacle, Twain took on the guise of a spiritual seeker who needed the support and prayers of Olivia's family in order to clean up his life.
Twain, influenced by Olivia's prodding, presumably converted. Twain wrote to his mother after his engagement to Olivia: "My prophecy was correct.…
Olivia's family was convinced Twain was a Christian and permitted the marriage. But was Twain's conversion an illusion? One scholar insists that Twain "was a man in love, wooing a woman he hoped to marry. His 'religious' feelings at that time, expressed in love letters to Olivia, disappeared as soon as the nuptials were over" (www.yorku.ca/twainweb/filelist/skeptic.html).
After their wedding, Twain ridiculed Olivia's beliefs and devotion. Soon Olivia's optimism began to wane, and her fervent faith cooled. Eventually she forsook her religion altogether, and a deep sorrow deluged Olivia's life. Mark Twain loved her and never meant to hurt her, but he had broken her spirit. He said, "Livy, if it comforts you to lean on your faith, do so."
She replied sadly, "I cannot. I do not have any faith left."
Twain often wished he could restore Olivia's faith, hope, and optimism, but it was too late.