Valentine’s Day brings to most Americans happy images of candy and pink hearts. But to others, February 14 brings sadness. To few has it brought more heartache than to Theodore Roosevelt, who lost both his wife and his mother on Valentine’s Day in 1884. Ironically, though, the loss that brought such profound sorrow to Roosevelt ultimately changed the nation for the better. It shaped Roosevelt’s political career by convincing him of the need to reform the nation’s cities. By triggering Roosevelt’s escape to Dakota Territory, the tragedy also provided the future president the cowboy credentials he needed to cement his political career.

In 1880, Roosevelt could hardly have anticipated the tragedy that would stun him four years later. February 14, 1880, marked one of the happiest days of his life. He and the woman he had courted for more than a year, Alice Hathaway Lee, had just announced their engagement. Roosevelt was over the moon: “I can scarcely realize that I can hold her in my arms and kiss her and caress her and love her as much as I choose,” he recorded in his diary. The next four years were, according to Roosevelt, “three years of happiness greater and more unalloyed than I have ever known fall to the lot of others.”

After they married in fall 1880, the Roosevelts moved into the home of Theodore’s mother, Martha Bulloch Roosevelt, in New York City. There, they lived the life of wealthy young socialites, going to fancy parties and the opera, and traveling to Europe. When Roosevelt was elected to the New York State Assembly in 1881, they moved to the bustling town of Albany, where the state’s political wire-pullers worked their magic. Roosevelt’s machine politician colleagues derided the rich Harvard-educated young man as a “dude,” and they tried to ignore his irritating interest in reforming society.

In the summer of 1883, Alice discovered that she was pregnant, and that fall she moved back to New York City to live with her mother-in-law. There, she awaited the birth of the child whom Theodore was certain would arrive on February 14. As headstrong as her father, Roosevelt’s daughter anticipated her father’s prediction by two days. On February 12, Alice gave birth to the couple’s first child, who would be named after her. Roosevelt was at work in Albany, and learned the happy news by telegram. But Alice was only “fairly well,” Roosevelt noted, and she soon began sliding downhill fast. She did not recover from the birth; she was suffering from something at the time called “Bright’s Disease,” an unspecified kidney illness.

Roosevelt rushed back to New York City, but by the time he got there at midnight on February 13, Alice was slipping into a coma. Distraught, he held her until he received word that his mother was dangerously ill downstairs. For more than a week, “Mittie” Roosevelt had been sick with typhoid. Roosevelt ran down to her room, where she died shortly after her son arrived at her bedside. With his mother gone, Roosevelt rushed back to Alice. Only hours later she, too, died.

On February 14, 1884, Roosevelt etched a heavy black X in his diary and wrote “The light has gone out of my life.” He refused ever to mention Alice again.

Roosevelt’s profound personal tragedy turned out to have national significance. The diseases that killed his wife and mother were diseases of filth and crowding—the hallmarks of the growing Gilded Age American cities. Mittie contracted typhoid from either food or water that had been contaminated by sewage; New York City did not yet treat or manage either sewage or drinking water. Alice’s disease was probably caused by a strep infection, which incubated in the teeming city’s slums and tenements. Roosevelt had been interested in urban reform because he worried that incessant work and unhealthy living conditions threatened the ability of young workers to become good citizens. Now, though, it was clear that he, and other rich New Yorkers, had a personal stake in cleaning up the cities.

The tragedy gave him a new political identity that enabled him to do just that. Ridiculed as a “dude” in his early career, Roosevelt changed his image in the wake of the events of February 1884. Desperate to bury his feelings for Alice along with her, Roosevelt escaped to Dakota Territory, to a ranch in which he had invested the previous year. There, he rode horses, roped cattle, and toyed with the idea of spending the rest of his life as a western rancher. The brutal winter of 1886-1887 changed his mind. Months of blizzards and temperatures as low as -41 degrees killed off 80% of the Dakota cattle herds; more than half of Roosevelt’s cattle died. Roosevelt decided to go back to eastern politics, but this time, no one would be able to make fun of him as a “dude.” In an era when the independent American cowboy dominated the popular imagination, Roosevelt ran as a western cowboy taking on corruption in the East. And, with that cowboy image, he overtook his eastern rivals.

Eventually, Roosevelt’s successes made establishment politicians so nervous they tried to bury him in the graveyard of the vice presidency. Then, in 1901, President McKinley’s assassination put Roosevelt—“that damned cowboy,” as one of McKinley’s advisers called him–into the White House. There, he worked to clean up the cities and champion the urban reforms that were the hallmark of the Progressive Era.