On the winter morning of January 31, 1861, Abraham Lincoln stepped inside a secluded farmhouse seemingly adrift on the vast Illinois prairie. The president-elect had left his hometown of Springfield only once in the eight months since garnering the Republican presidential nomination—in order to finally meet his running mate, Hannibal Hamlin, in person—but he had one special goodbye that he needed to deliver in person before departing Illinois for his inauguration. Inside that cozy farmhouse tucked underneath a blanket of snow, Lincoln bent down his lanky frame and embraced the wizened woman he called “Mother,” not the woman who gave birth to him, however, but the stepmother who helped to set him on the path to the White House.

Nancy Hanks Lincoln, who gave birth to the Great Emancipator on February 12, 1809, had instilled the virtues of honesty and compassion in her son and sowed the seeds of his intellectual curiosity. Although lacking a formal education of her own, Nancy Lincoln impressed the importance of learning and reading on her young boy as they moved about the Kentucky and Indiana frontier. When his mother suddenly died in 1818 after drinking milk tainted with poisonous white snakeroot, 9-year-old Abraham was devastated.

Fourteen months later, Lincoln’s father, Thomas, returned to his former haunt of Elizabethtown, Kentucky, and called on Sarah Bush Johnston. The pair had known each other from the Lincolns’ former time in Elizabethtown, and as soon as the widow Johnston, who had lost her husband in an 1816 cholera epidemic, answered the knock on the door, Thomas proposed. Once he agreed to pay off her late husband’s outstanding debts, Sarah accepted the matrimonial offer. Widow and widower wed on December 2, 1819.

Thomas Lincoln brought Sarah and her three children back to his small Indiana cabin to live with his two surviving children, Abraham and sister Sarah. Thomas Lincoln’s new wife found Indiana to be “wild and desolate,” and the same could have been said about feral young Abraham. Sarah Lincoln dressed him up so that he “looked more human” and brought a woman’s touch to their sparse cabin. “She very quickly turned things around,” says Jeff Oppenheimer, author of “That Nation Might Live,” an historical novel based on his extensive research into the strong bond between Lincoln and his stepmother. “They were living on dirt floors. Sarah had Thomas put in a wooden floor, fix the roof and whitewash the house. Within weeks, it was a whole new household. They became human again.”

As testimony to the nurturing of Nancy Lincoln, whom her son began to call his “angel mother,” Sarah Lincoln found her new stepson to be a model child. “Abe was the best boy I ever saw,” she said years later after his death. “I can say what scarcely one woman—a mother—can say in a thousand and it is this—Abe never gave me a cross word or look and never refused in fact, or even in appearance, to do anything I requested.” Sarah also vouched for Honest Abe’s long-standing reputation for integrity. “He never told me a lie in his life—never evaded, never equivocated, never dodged.”

Sarah filled the enormous void in Lincoln’s life after the loss of his biological mother. Although likely illiterate herself, she furthered Nancy’s work in cultivating Abe’s reading comprehension and intellect. Sarah quenched her stepson’s thirst for knowledge by providing him with books to read. “Sarah had an appreciation for the value of an education,” Oppenheimer says. “She recognized early on there was something special about this boy and defended his right to pursue his intellectual development.”

Stepmother and stepson quickly forged a loving bond. “His mind and mine, what little I had, seemed to run together, move in the same direction,” Sarah said. She treated Lincoln as if he was her flesh-and-blood by offering love, kindness and encouragement. He returned the affection, calling her “Mother.” In 1861, Lincoln confided to a relative that his stepmother “had been his best friend in this world and that no son could love a mother more than he loved her.”

When Thomas Lincoln died in 1851, Sarah found herself a widow once again. Lincoln helped to support his stepmother and maintained a 40-acre plot for her on the Illinois plains. As Lincoln departed his stepmother’s side on his 1861 visit, tears welled up in her blue-gray eyes. Sarah had never wanted him to run for president, fearful that something would happen to him. When her premonition was fulfilled four years later and the news from Ford’s Theatre arrived, Sarah pulled her apron over her face, began to sob and cried out, “They’ve killed him. I knew they would. I knew they would.”

When Sarah died in 1869, she was buried in a black woolen dress given to her by her stepson during their final reunion, a token of appreciation for all she had done for him. “She recognized a boy of tremendous talent and saw the diamond when virtually everyone else around this gangly, awkward boy saw the rough,” Oppenheimer says. “That’s what mothers do.”