Scientist

There were countless major scientific breakthroughs during the last millennium. To choose one scientist who stands out over the rest requires weighing not just the individual's accomplishments, but also how he or she changed the process of scientific discovery itself. This criterion leads us to Italian physicist and astronomer Galileo Galilei, who pioneered important aspects of what today is known as the scientific method.

Galileo was born near Pisa in 1564—the same year Shakespeare was born and Michelangelo died. In 1589, while a professor of mathematics at the University of Pisa, Galileo began to conduct experiments testing Aristotle's theory that the speed of a fall is dependent on the weight of the falling object. Others had questioned the theory in the past, but Galileo was the first to use scientific experiments to disprove it—by dropping objects of different weights from the Tower of Pisa, legend has it. This method of developing a hypothesis and then performing an experiment to see if the hypothesis was true or false established physics as a precise science, bringing science as a whole out of the realm of natural philosophy and into the modern era.

Galileo's contributions to scientific knowledge were also significant. He built the first telescope for astronomical purposes, observed that the Milky Way consisted of stars, articulated the laws of bodies in motion, and discovered the Moon's craters, Jupiter's largest four satellites, sun spots, and the phases of Venus.

Galileo's ideas generated much controversy at the time, none more than his support for the then-heretical notion that the Earth was not the center of the universe. In his book Dialogue on the Two Chief World Systems (1632), Galileo argued for the Copernican theory, which held that the Sun was the center of the solar system. After the book was published, Galileo was charged with and found guilty of heresy by the Roman Catholic Church. He died in 1642, but the fires of scientific revolution that he started still burn bright.

Statesman

George Washington was not a social philosopher who helped develop the concept of democracy, but he definitely fostered it and ensured its success as a political system. With the war for independence from Great Britain won, the founders of the United States lacked a clear vision of what their new government should look like. Already a war hero, Washington was instrumental in shaping a model of government that has worked successfully for more than 200 years—an oft-imitated system that has withstood destructive forces such as a wrenching civil war and corruption at the highest levels. Some of the crafters of the Constitution of the United States preferred a monarchy such as England had, but Washington rejected the idea and led the way in forging the democratic system that has endured to the present day.

Before he was a statesman, Washington was a soldier of the highest caliber. After distinguishing himself fighting for the British army during the French and Indian War (1754-1763), Washington was elected commander in chief of the colonies' Continental Army in 1775. He faced a daunting task, taking on Great Britain's large standing army and a navy second to none in the world. His army was small, poorly trained, and lacking in supplies and weaponry. Washington and his troops fought bravely for eight long years, overcoming a more powerful enemy to win independence from Britain and establish a new nation based on the principle of liberty.

After the war, Washington longed to return to his Virginia farm. Instead, realizing the fledgling government was still in danger of failing, he helped craft and ensure passage of the Constitution of the United States. He then accepted the unanimous will of the electoral college to serve as the nation's first president. “I walk on untrodden ground,” Washington said, realizing that everything he did in office would establish a precedent. Thus Washington invented the model for the presidency that has been preserved to this day: limiting himself to two terms, respecting the separate powers of the legislative and judicial branches of government, and fostering the concept of a strong central government.

In 1799, just two years after he finished his presidency, Washington died on his Mount Vernon farm. The nation mourned a man who was at the same time one of the greatest military figures in history and one of the most important political figures of the millennium. More than any single monarch, more than any groundbreaking politician, Washington was the driving force behind what is arguably the most successful form of government of the second millennium.