The most important development of the past thousand years has been the growth of liberty, both because liberty is important in its own right and because it is what has made virtually all of the other achievements of humanity possible, as well, from science to art to material well being.

For that reason, I would locate the first of the most significant moments of the past thousand years in March of 1075, when Pope Gregory VII issued the Dictatus Papae, in which he formally announced the independence of the church from the state and the power of the church to check the state. As Article 27 states, “The Pope may absolve subjects of unjust men from their fealty.” The great historian Lord Acton wrote, “To that conflict of four hundred years we owe the rise of civil liberty … the aim of both contending parties was absolute authority. But although liberty was not the end for which they strove, it was the means by which the temporal and the spiritual power called the nations to their aid.”

Second on my list would be the growth of European constitutionalism. This was a broadly European movement, but especially notable for the Anglo-American tradition is, of course, the issuance of Magna Carta on June 19, 1215. The Magna Carta explicitly limited the royal power, established the principle of the consent of the governed and guaranteed rights of due process, freedom of trade and more. These and other provisions later found their way into the U.S. Constitution.

Third would be the invention of movable type in Europe around 1436 or 1437 by Johann Gutenberg. This tremendous innovation broke the monopolies of the privileged few over knowledge. The printed book initiated an information sea change that is still going on; the worldwide Web is just the latest chapter in the freeing of information made possible by Gutenberg.

Fourth, in my view, is the rebirth of constitutionalism after its eclipse by absolutism and mercantilism. The struggle to place limits on government and at the same time to expand greatly the popular enjoyment of liberty took place dramatically in the 16th, 17th and 18th Centuries in the revolt of the Dutch against their Spanish overlords, the revolts of the English against the Stuart kings and the revolt of the Americans against the British crown and parliament. As the historian John Lothrop Motley wrote, “The rise of the Dutch Republic must ever be regarded as one of the leading events of modern times.… The maintenance of the right by the little provinces of Holland and Zealand in the 16th, by Holland and England united in the 17th, and by the United States of America in the 18th centuries forms but a single chapter in the great volume of human fate; for the so-called revolutions of Holland, England and America, are all links of one chain.”

Or as John Figgis, professor of modern history at Cambridge University, noted at the turn of the century, “The sonorous phrases of the Declaration of Independence … are not an original discovery, they are the heirs of all the ages, the depository of the emotions and the thoughts of 70 generations of culture.”

The fifth item on my list is the rise and fall of the totalitarian state. As the classical liberalism that inspired the American revolution began to wane, various forms of collectivism — notably nationalism, racism and socialism — rose to challenge liberty. The classical liberal journalist E. L. Godkin wrote in chilling and depressing editorial on August 9, 1900, “Only a remnant, old men for the most part, still uphold the liberal doctrine, and when they are gone, it will have no champions.” He predicted that the 20th Century would be a century of war and statism: “The old fallacy of divine right has once more reasserted its power, and before it is again repudiated, there must be international struggles on a terrific scale.”

Those struggles — against fascism, National Socialism and communism — are now behind us. The struggle for liberty is not over, but, on the eve of the third millennium, the prospects are bright again.