1633 by David Weber and Eric Flint

When a small American town from the year 2000 is suddenly transported to war-torn Europe in 1633, history itself shatters. Surrounded by empires, kings, and chaos, the people of Grantville refuse to bow to tyranny. Armed with modern knowledge, technology, and the stubborn spirit of freedom, they ignite a revolution that will forever alter the destiny of the Old World. As alliances are forged and battle lines drawn, courage, innovation, and humanity collide in a breathtaking saga of what happens when the future confronts the past.