Two hundred years ago this month a rich Latin American tourist, jaded at just 22 years of age from womanising and gambling, dropped to his knees while visiting Rome and in front of his tutor swore "not to give rest to my arm nor my sword until the day when we have broken the chains of Spanish power which oppress us".
That same month - in fact, exactly 200 years ago today - one of the great voluptuaries of the age set sail for the New World after two decades in the Old hoping to raise a force with which to launch the liberation of his homeland from the Spanish.
From these unlikely points of departure began South America's epic struggle for independence, whose successes will be remembered in bicentennial celebrations across that continent in the coming two decades.
The great hero of that struggle was the Venezuelan Simón Bolívar, though his tutor would have been hard pressed to imagine that his dissolute young charge would live to carry through on his Roman promise.
Bolívar's enduring reputation today almost completely outshines that of Francisco de Miranda, the man who, on August 31st 1805, headed off with the intention of a full frontal armed assault on Spain's American possessions. But Miranda was in his own day perhaps the most famous South American alive.
Like the younger Bolívar, he was the rich son of a wealthy family from Caracas. He had fought for Spain in North Africa and in the American War of Independence, shortly after which he was accused of treason. He deserted with the intention of travelling back to Spain to clear his name. But he never quite made it to Madrid, instead arriving in London advocating independence for Spain's American possessions.
It seemed a preposterous idea. Spain was one of the world's great military powers and ruled with an iron fist over one of history's largest, longest-lasting and most lucrative empires. But to Miranda, a child of the Enlightenment, it seemed obvious that the poverty and backwardness of the Americas was the consequence of Spain's reactionary rule.
Having settled on independence as the corrective he now set out to promote the idea around Europe. For reasons that had little to do with politics and more with the dash he cut through Old World high society, this tour turned Miranda into one of the social phenomena of the age.
Rich, handsome and cultured (by the end of his life he had collected one of the world's most impressive private libraries), he seemed to find all the most important doors open for him. He was also a compulsive philanderer, bedding women from maids to - it is rumoured - Catherine the Great. In a sense he was an early prototype of a sort Europe came to know well over subsequent centuries - the rich, South American playboy abroad. He recorded everything in his diaries, which secure his reputation as one of history's great Latino machos.
It was the turmoil started by the French Revolution that turned Miranda from Europe's most seductive guest into a political player. He started drawing up grand military schemes for freeing the Americas, hoping to attract the interest of ambitious minds in Paris and London who had started eyeing up Spain's possessions abroad.
It was in the hope of promoting one of these schemes that Miranda went to revolutionary Paris in 1792. He was given an army but directed to the Low Countries to beat back the counter-revolutionary invasions. This he helped do - his name is engraved on the Arc De Triomphe to commemorate his exploits. But he subsequently fell foul of The Terror, and only narrowly escaped the guillotine.
Denied support for his schemes in Europe, Miranda returned to the New World in 1805. He headed to the US and within a year had kitted out a quixotic expedition of 200 men in three boats who sailed off to take on the Spanish empire. He made land in Venezuela, captured a town and issued some proclamations, but then had to flee in the face of a Spanish counterattack.
The whole operation was a fiasco. Nonetheless Miranda returned to London a hero. His daring had caught the public imagination and had won for him the role of leader of South America's independence movement, just when Napoleon's takeover of Spain was giving such movements life.
Although they had not met before, Miranda's reputation was such that when a now 27-year-old Simón Bolívar led a delegation to London in 1810 looking for British support for Venezuelan independence, he quickly sought out his political idol.
Bolívar failed to secure any British aid but did convince Miranda that he was the leader people back home were looking for. Miranda returned and events started off better than they had in 1806, Venezuela formally declaring its independence in 1811 with Miranda appointed its first ruler.
But Spain regrouped, counter-attacked and routed the rebels who fell into squabbling among themselves. Miranda sued for peace. In a rage Bolívar saw this as treason and handed Miranda over to the Spanish before he could depart for Europe.
Bolívar never showed any regret for this betrayal. Young, and soon free again, he went on to pursue the goals Miranda had first laid out - an America free of Spanish rule. This was accomplished within two decades of Miranda's first disastrous campaign of 1806.
Miranda never lived to see his dream realised. He was locked up in La Carraca prison in Cadiz where he died, aged 66, on Bastille Day in 1816, a vengeful Spain refusing all entreaties to release him. To the very last, it understood the terrible damage that Miranda had done to it.