The most powerful man on his continent; a poet and a cosmopolitan; facing religious rebellion within his domain—these phrases describe both the Holy Roman Emperor Charles V and the Turkish sultan Suleyman the Magnificent, two dynamic young sovereigns who ruled over colliding worlds in the early 16th century. Their battle for Europe ended the Renaissance, began the Reformation, and brought Islam to the gates of Vienna.

Historian James Reston Jr. vividly recounts this conflict. While Shiites in the eastern Ottoman Empire were battling the Sunni Turks’ repression of their “heresy,” Charles V faced the “heresy” of Martin Luther and his followers, as well as a French incursion by land and sea. The restless Turks became convinced that the Ottoman Empire could expand into Europe. For 16 turbulent years (1520-1536), the epic clash between Europe and the Ottoman Empire shook the world. The resulting border established between Islam and Christendom holds to this day.

Reston is the author of Warriors of God, Galileo: A Life, and 12 other books. Defenders of the Faith: Charles V, Suleyman the Magnificent, and the Battle for Europe, 1520-1536 (Penguin Press) is available for signing after the program.