Isaac Newton and Gottfried Leibniz are two prominent Enlightenment Era scientists and mathematicians. Seemingly they both independently devised a system of calculus that allowed them to make calculations on things previously impossible. It is generally accepted that Newton invented calculus first, but as he did not publish this information for decades scholars have to rely on clues in his publications and on Newton's word (notoriously unreliable). The two men battled for acclaim for the invention during their lifetimes, but it is Newton who is most commonly remembered as the inventor of calculus (at least in the English speaking world), despite the fact that Leibniz was the first to publish on the matter. Calculus was vital to some of the scientific breakthroughs of Newton's lifetime and has been continued to be ever since. 

The geocentric model of the universe was originally developed by many ancient civilizations, and popularized by the Greek philosopher and scientist, Aristotle. It was widely accepted by scientific-minded individuals for over a thousand years. In the geocentric model, the Earth is at the center of the universe, and everything else orbits around it; however, in the sixteenth century, the Polish astronomer, Nicholas Copernicus, developed his theory that the sun was in fact the center of the universe. This event is called the Copernican Revolution, and his model was called the heliocentric model of the universe.

Mary Wollstonecraft wrote A Vindication on the Rights of Women, in 1792. In the text she argues that women are not naturally inferior or less intelligent than men, but merely appear so because they were no allowed an education and were forced to be subservient to men. She imagines a society founded on reason and equality, in which women are given every right and opportunity that men are given. 

Voltaire was an Enlightenment-Era philosopher who was most famous for his vehement attacks on the established religious orders—particularly the Catholic Church. He wrote passionately, advocating for freedom of religion and the separation of church and state. This naturally caused Voltaire to be condemned widely by the powers that be (although he was a good friend of Catherine the Great), and he had many causes to fear for his life, but he never stopped his polemical writings. His most famous work, Candide, is a scathing critique of the established order of the European world.

A Treatise of Human Nature and An Enquiry Concerning Human Understanding are two of the most famous works of the Scottish Enlightenment philosopher David Hume. Whilst you might not have recognized the works as immediately belonging to Hume, their titles ought to have been a clue. Hume was primarily concerned with understanding the relationship between human nature and human understanding. He was a particularly prominent supporter of empiricism and moral relativism.

Adam Smith's Wealth of Nations is the seminal economic text of the Enlightenment era. In it, Smith presents his arguments in favor of laissez-faire economics, or free-market Capitalism. The book was widely influential among the governments and thinkers of his era and continues to be influential to this day.

The Encyclopedie is one of the most famous works of the Enlightenment period. It was written by Diderot, with the help of many other famous writers of his era. The aim of the Encyclopedie was to collate all the knowledge of the Enlightenment into one book that could be widely disseminated around Europe. It was read by the Enlightened despots Catherine the Great and Maria Theresa, among others. 

Cesare Beccaria was an Italian thinker of the Enlightenment who is best known for his treatise On Crimes and Punishments, in which he condemned torture and the death penalty. John Locke and Voltaire were philosophers whose works covered a greater variety of ideas, such as natural and civil rights, religion, and political philosophy. Denis Diderot was a French Enlightenment philosopher best known for leading the effort to compile the Encyclopedie, a massive general encyclopedia that was meant to incorporate all of the world's knowledge.

Alexander II is often called "Alexander the Liberator" because in 1861, he ended the centuries long economic system of serfdom by emancipating the serfs. Serfdom was effectively slavery by another name. A serf was the property of his or her landowner and could not move without the landowner's permission. Serfs were expected to work the land and provide for their master's prosperity.

The Russian serfs were emancipated in 1861 by Tsar Alexander II. The institution of serfdom was very similar to the institution of slavery and underpinned the whole feudal system of economic and social life throughout much of Europe from the fall of the Roman empire until the Industrial Revolution. It is worth noting that the emancipation of the serfs in Russia and the slaves in the United States happened at very much the same time. Clearly there was a global movement away from forced labor.