It was the worst of times—1527—one of the most trying years of Luther’s life. It’s hard to imagine he had the energy or spirit to compose one of Christendom’s most memorable hymns.

On April 22, a dizzy spell forced Luther to stop preaching in the middle of his sermon. For ten years, since publishing his 95 Theses against the abuse of indulgences, Luther had been buffeted by political and theological storms; at times his life had been in danger. Now he was battling other reformers over the meaning of the Lord’s Supper. To Luther, their errors were as great as those of Rome—the very gospel was at stake—and Luther was deeply disturbed and angry. He suffered severe depression.

Then, on July 6, as friends arrived for dinner, Luther felt an intense buzzing in his left ear. He went to lie down, when suddenly he called, “Water … or I’ll die!” He became cold, and he was convinced he had seen his last night. In a loud prayer, he surrendered himself to God’s will.

With a doctor’s help, Luther partially regained his strength. But this depression and illness overcame him again in August, September and late December. Looking back on one of his bouts, he wrote his friend Melanchthon, “I spent more than a week in death and hell. My entire body was in pain, and I still tremble. Completely abandoned by Christ, I labored under the vacillations and storms of desperation and blasphemy against God. But through the prayers of the saints [his friends], God began to have mercy on me and pulled my soul from the inferno below.”

Meanwhile, in August, the plague had erupted in Wittenberg. As fear spread, so did many of the townspeople. But Luther considered it his duty to remain and care for the sick. Even though his wife was pregnant, Luther’s house was transformed into a hospital, and he watched many friends die. Then his son became ill. Not until late November did the epidemic abate and the ill begin to recover.

During that horrific year, Luther took time to remember the tenth anniversary of his publication against indulgences, noting the deeper meaning of his trials: “The only comfort against raging Satan is that we have God’s Word to save the souls of believers.” Sometime that year, Luther expanded that thought into the hymn he is most famous for: “A Mighty Fortress Is Our God.” This verse, translated by Frederick Hedge in 1853, comes from one of more than sixty English versions:

And though this world with devils filled
should threaten to undo us,
We will not fear, for God has willed
his truth to triumph through us.
The prince of darkness grim? We tremble not for him.
His rage we can endure, for lo! his doom is sure.
One little Word shall fell him.

Mark Galli is associate editor of Christian History.