Like many legends, it is perhaps a little overstated in the retelling - though only a little. On October 28 every year, Greek communities around the world celebrate the 'anniversary of the No'. At dawn on that day in 1940, Benito Mussolini demanded that his army be allowed to enter Greece and occupy strategic positions.
Prime Minister Ioannis Metaxas is said to have responded defiantly with a single word: "Oxi" - meaning 'No'. Greeks took to the streets in large numbers, chanting "Oxi!"
The one-word answer is a proud tradition of that part of the world, dating back to the Ancient Spartans. Phillip II of Macedon is said to have sent the Spartans a message with various demands, saying "Unless you agree to my demands I will wage war on you and, if I win this war, you will be slaves forever." The Spartans responded with the single word "If". Phillip did not attack. From such Spartan (Lacedaemon) brevity comes the modern word 'laconic'.
Similarly, the word 'Oxi' means more than just no; it is a symbol of defiance. Knowing that refusal would mean all the hardship of war, Greeks had the courage to do precisely that - and in the clearest possible terms.
On Sunday, Greeks will go to the polls for a referendum on whether they will accept punitive bailout terms. A quick reminder of how countries normally recover from financial crisis: their currency devalues naturally, causing their goods and services to be incredibly cheap on global markets, creating jobs and an economic boom.
With Greece shackled to the euro, it cannot take control of its own economy in this most basic way. At this stage any other country would be defaulting on its debt. But Tuesday's relatively minor Greek default was bitterly opposed - not because of the consequence to the euro, and the political project.
The eurozone puts its own will above Greek sovereignty, attacking the very decision to allow the people a say on such punitive terms. The latest opinion poll suggests 46% will vote 'No' to 37% for 'Yes'.
Europe stepped in to prevent Greek democracy once before, so it has form in this respect. Expect an unprecedented level of cajoling, threats and scaremongering from Europe to attempt to bully Greece into voting 'Yes'. They have already begun to suggest that Greece will be forced out of the euro if they don't vote Europe's way in the referendum. There is no legal basis for this to happen, but if it did - so what? It might cause some temporary short-term pain, but it would provide the Greek economy with the tools (devaluation in particular) needed to recover. After all, who wouldn't be rushing to take advantage of the weak drachma to enjoy a cut-price Greek holiday? Would Greek olive oil not become very attractive to British supermarkets? The Greek economy would bounce back far quicker with the picture of Apollo back on their banknotes than with the picture of a generic, non-existent bridge.
Will the Greek people fall for the eurospin, or will they show that same defiant 'Oxi' spirit which epitomises all that is best about Greece throughout the ages? The word 'Oxi' may literally translate as 'No', but it means so much more than that. It's not negative but a positive assertion. An assertion of rights, of self-determination, of what it means to be Greek.
On Sunday the complex referendum question in practice means only this: Do the Greek people accept the right of Europe to overrule their democratically-elected governments?
Will the Greek people strike a blow for freedom, not just theirs but ours too? For if the answer is indeed 'Oxi', then who knows? Perhaps in generations to come July 5 will join October 28, and two 'anniversaries of the No' will be celebrated.