Sultan Murad IV decreed death to coffee drinkers in the Ottoman Empire. King Charles II dispatched spies to infiltrate London’s coffeehouses, which he saw as the original source of “false news.” During the Enlightenment, Voltaire, Rousseau and Isaac Newton could all be found talking philosophy over coffee. The cafés of Paris sheltered revolutionaries plotting the storming of the Bastille and later, served as the place authors like Simone de Beauvoir and Jean-Paul Sartre plotted their latest books.

History is steeped in ideas sparked over cups of coffee. Here's a rundown of the revolutionary power of the commonplace café.

Coffee houses began in the Ottoman Empire. Since liquor and bars were off-limits to most practicing Muslims, coffeehouses provided an alternative place to gather, socialize and share ideas. Coffee’s affordability and egalitarian structure—anyone could come in and order a cup—eroded centuries of social norms. Not everyone was pleased by this change.

In 1633, Sultan Murad IV decreed that the consumption of coffee was a capital offense. Murad IV’s brother and uncle had been killed by janissaries, infantry units who were known to frequent cafes. The sultan was so dedicated to catching coffee sippers in the act that he allegedly disguised himself as a commoner and prowled Istanbul, decapitating offenders with his hundred-pound broadsword.

Ottoman sultans issued and retracted coffeehouse bans well into the 18th century to prevent the gathering of dissidents. But by then, coffeehouses had already spread to Europe and were striking fear into the hearts of kings.

Pasqua Rosée opened the first coffee house in London in 1652, prompting a revolution in London society. “British culture was intensely hierarchical and structured. The idea that you could go and sit next to someone as an equal was radical,” says Markman Ellis, author of The Coffee House: A Cultural History. The defining feature of English coffee houses were communal tables covered with newspapers and pamphlets where guests would gather to consume, discuss and even write the news. “Coffeehouses were the motor of the news industry in 18th-century London,” Ellis explains.

King Charles II’s father, Charles I, had been decapitated during the English Civil War, so he was understandably paranoid about his subjects gathering to talk politics. On June 12, 1672, Charles II issued a proclamation to “Restrain the Spreading of False News, and Licentious Talking of Matters of State and Government,” which read in part: “men have assumed to themselves a liberty, not only in Coffee-houses, but in other Places and Meetings, both public and private, to censure and defame the proceedings of State by speaking evil of things they understand not.”

To combat this “evil,” Secretary of State Sir Joseph Williamson embedded a network of spies in London coffee houses and in December of 1675, Charles II went as far as ordering the closure of all coffee houses in London. The ban lasted just 11 days. The people had spoken: Coffee was here to stay.

The ban’s failure was history’s gain: The very type of open discussion Charles II feared led to the explosion of new ideas during the Enlightenment. In Oxford, locals had begun calling coffee houses “penny universities” because for the cost of a cup of coffee, you could gain access to intellectual discussions and, critically, sober debate. At a time when beer was often a safer drinking option than water, this was no small thing.

In his diaries, Samuel Pepys recorded the stimulating conversations he overheard at the coffee houses he frequented. Most coffee houses catered to a specific clientele; the Grecian Coffee House near Fleet Street was a meeting place for Whigs as well as members of the Royal Society like Isaac Newton, who once dissected a dolphin on one of its tables. Meanwhile, poets John Dryden, Alexander Pope and writer Jonathan Swift held court at Will’s Coffee House.

At Jonathan’s Coffee House in Exchange Alley, stockbrokers crowded around to trade shares after official trading hours had closed… giving birth to the London Stock Exchange. Lloyd’s Coffee House was a nexus for sailors and merchants, who dreamed up Lloyd’s of London insurance market within its walls. Coffee’s influence began to spread as travelers returned to their home countries, hooked on caffeine and craving conversation.

Frederick the Great of Germany was so against coffee that he attempted to outlaw the drink outright in favor of beer on September 13, 1777. Afraid that the importation of coffee was costing his kingdom (and his highness) business, he required all coffee sellers to register with the crown, denying licenses to all but a few friends of the court and employing former soldiers to work as “sniffers,” roaming the streets to detect any contraband coffee roasters. His strong opinions on coffee were recorded in a 1799 letter:

"It is despicable to see how extensive the consumption of coffee is … if this is limited a bit, people will have to get used to beer again … His Royal Majesty was raised eating beer-soup, so these people can also be brought up nurtured with beer-soup. This is much healthier than coffee."

The ban was lifted after his death, and the healthy debates waged in coffee houses continued.

Coffee was seen as a patriotic drink in the colonies after the Boston Tea Party when drinking tea fell out of fashion. At the time, American taverns served coffee alongside liquor, and the Green Dragon Tavern in Boston was nicknamed the “Headquarters of the Revolution” by Daniel Webster for housing many meetings of the Sons of Liberty leading up to and during the Revolutionary War.

Over in New York, Merchant's Coffee House was known for its gatherings of patriots eager to break free from George III. In the 1780s, it became the site where merchants organized to create both the Bank of New York and reorganize the New York Chamber of Commerce.

Across the pond, Benjamin Franklin wrote his “Open Letter to Lord North” satirizing the king’s power over the colonies from the Smyrna Coffee House in London.

Parisian Cafés, with their social egalitarianism, were an ideal location for Republican agitation and organization during the French Revolution. A royalist of the era complained:

“Where does so much mad agitation come from? From a crowd of minor clerks and lawyers, from unknown writers, starving scribblers, who go about rabble-rousing in clubs and cafés. These are the hotbeds that have forged the weapons with which the masses are armed today.”

The Paris's Café de Foy hosted the call to arms for the storming of the Bastille. During the Enlightenment, the Café Procope had been the place where men like Rousseau, Diderot and Voltaire gathered to hone their philosophies and art. After the Revolution, Parisian café culture again became the haunt of writers and thinkers gathering to exchange ideas and work on their next masterpiece.

Expatriates like Ernest Hemingway, Gertrude Stein, F. Scott Fitzgerald and T.S. Eliot met at La Rotonde. French poet and critic Apollinaire worked on his art review, “Les Soirées de Paris,” at the Café de Flore, sitting alongside André Breton. By the mid-century, Simone de Beauvoir and Jean-Paul Sartre debated and created philosophies from their tables.

From the Ottoman Empire to England, the United States to France, coffeehouses led to a meeting of the minds that inspired new waves of thought.