Long before microphones, television or podcasts existed, the human voice was already igniting passions in the audience. We will never know what Alexander the Great said to stop the mutiny of his troops in Opis, around 324 BC, but something in his words must have moved the hearts of that tired and resentful army to stop their bloodlust.

Nor do we know the words of Hernán Cortés when he decided to burn the ships -in fact, he sank them- to enter with a miniscule army of 400 men into the vast domains of the Aztec Empire. Again, that harangue must have convinced the soldiers to commit a hopeless folly: to cut off all means of escape to enter the realm of the unknown.

We may be surprised to find that most of the speeches made in the history of mankind have been lost forever. Like the ships in Mexico, the voices of the past no longer exist. But precisely because most of the speeches of history have disappeared, great literature has been able to speculate with them.

The undisputed master in this field was William Shakespeare, author of some of the most famous speeches ever delivered. We imagine, for example, framework Antonio delivering an oration before the bloodied body of Julius Caesar, a masterful class of irony and how rhetoric can be used to say one thing, but imply something quite different without naming it. Despite the apparent solemnity of speech, framework Antony suggests that neither Brutus' intentions were so honorable, nor Caesar so ambitious, and someone had to take over.

Other speeches, such as Henry V's speech at the battle of Azincourt, have gone down in history for the inspirational power of their images. Shakespeare imagines the English army suddenly cornered by the French in their flight towards the English Channel. In an inspired speech, King Henry manages to raise the morale of the troops by baptizing all the men ready to die in battle as "blood brothers", leading them by imagination to the day when, back in England, they can tell their exploits to their children and grandchildren, proudly showing their wounds.

But it's not all literature: when Abraham Lincoln took the floor to speak at Gettysburg, more than 50,000 soldiers lay in the graves of the national cemetery just a few feet from the podium. On that cold December 1863, Lincoln had the daunting task of summarizing the lessons of the Civil War, and he did it in just two or three minutes, in ten sentences and less than 300 words.

Most likely, few heard its content: without microphones and with so few words, those in attendance were probably unaware of what they had just witnessed. Lincoln was leaving for posterity one of the best definitions of democracy: "Government of the people, by the people, for the people". However, it was a long time before the speech became famous, with the printing and reprinting of those lines.

For speeches to have an immediate effect on an entire country, it would be necessary to wait for the invention of radio. On October 30, 1938, Orson Welles decided to put radio listeners on test with an experiment that would cause panic and astonishment: he began to narrate in real time an invasion of Martians on planet Earth. The speech produced a collective hysteria in the listeners that lasted a few hours, enough time to discover that it was a joke and to show the world the power of modern mass media.

In reality, the hysteria provoked by Welles' speech had a very real correlate: a month earlier, Hitler had signed a agreement with France, Italy and the United Kingdom by which Germany incorporated a substantial part of Czechoslovakia. Thus, when two years later the Germans expelled the last Franco-British battalions at Dunkirk, Winston Churchill had to defend the indefensible. In a series of memorable speeches, the Prime Minister offered the public an uncertain future -"save blood, work, tears and sweat" - but also "the most glorious hour" of the British Empire. Few speeches have so starkly posed a tragedy; and few had so much impact to inspire heroism in the darkest hour.

With the age of television, the rules of the game changed again. Speakers now had to be not only masters of rhetoric, but also captivate the audience with a sweeping smile and mastery of nonverbal language.

The first presidential debates broadcast on television showed the world the duel at the top between two titans of oratory: John F. Kennedy and Richard Nixon. The former would go down in history as one of the most charismatic presidents in history thanks to the impact of his speeches on television. Many remember the slogan of his inaugural speech - "Ask not what your country can do for you; ask what you can do for your country"- an impression that contrasts vividly with the stern expression the president's face took on during the Cuban missile crisis, warning the Soviets that "aggressive behavior, if allowed to continue unchecked and unchallenged, leads ultimately written request to war."

discussion between John F. Kennedy and Richard Nixon (1960). Dave Winer / Flickr, CC BY

Today, we know that Kennedy meant business, and that fortunately the crisis was averted at the last moment. There was a noble, sometimes even reckless, candor in his words that was surpassed only by a contemporary: Martin Luther King Jr.

If there is one thing that makes the civil rights hero memorable, it is that speech delivered in Washington on August 28, 1963: "I have a dream". In just over six minutes, King recounted the beauty and tragedy of his country. Like Lincoln, he was convinced that the "sleeping giants" of the Constitution would awaken: equality and freedom for all humans.

Few speeches are as timeless as this one. Like all great orators, Luther King knew how to convey an emotion that transcended boundaries that went far beyond skin color. That speech was delivered for the men and women of his time, but also for our own.

Shakespeare could not hear framework Antonio, but we can hear Kennedy or Luther King. In this world of instantaneous rhythms, full of immediacy, going back to these speeches -so slow and paused many times- can bring us back, even if only for a few minutes, to a calmer and, perhaps, more reflective world.