Sept. 11 marks a far older tragedy for Catalans -- the day in 1714, amid the War of Spanish Succession, when Catalan forces holding out in Barcelona succumbed to the forces of the Bourbon King Philip V. Ever since, this northeastern region has been more tightly in the Spanish fold. Sept. 11 became Catalonia's national day, an occasion once suppressed by the fascist Franco dictatorship, but now cause for an outpouring of Catalan pride and separatist aspirations.

As many as 1.8 million people marched in Barcelona on Thursday in support of Catalonia's latest bid for independence, according to the event's organizers. (Spanish Interior Ministry officials say the figure was 525,000.)

The streets of this elegant coastal city were a sea of red-and-yellow, Catalonia's nationalist stripes. On the same day in 2013, organizers attempted to form a 250-mile-long human chain marking Catalonia's right to self-determination. This time, they formed a giant "V" in Barcelona, symbolizing their desire to vote on the question of secession. About  55 percent of the region's more than 7.5 million people want independence, according to local polls.

Separatists in Catalonia plan to stage a referendum on independence in November, but authorities in Madrid are adamant that the vote should not pass and would be considered illegal. But Catalan leaders see hope in the momentum now propelling the "Yes" camp in Scotland toward next week's referendum there on whether Scotland should break away from the United Kingdom.

Spanish Prime Minister Mariano Rajoy has warned that an independent Catalonia would be isolated and vulnerable, outside the European Union and in need of a new currency. But Artur Mas, president of Catalonia, thinks an independent Scotland can show the way. "The first [factor] will be the reaction of European leaders. I am sure they will accept the result of the Scottish referendum," said Mas this week in an interview with the Financial Times. "The second is that negotiations will start very quickly between Edinburgh, London and Brussels to keep Scotland within the E.U. Both things are very important for Catalonia."

"Once independence is a reality, everybody in the economy accommodates to the new situation," Mas added.

Catalonia has long been one of Spain's main industrial engines, representing one-fifth of the whole country's economy, and its politicians believe its future would be rosier if it was free of the wider dysfunctions of the Spanish economy. Madrid, though, has been far less accommodating of Catalan aspirations than the British government under Prime Minister David Cameron has been of Scotland's move toward independence. Mas told the Financial Times that such Rajoy's intransigence is "putting [Spanish] democracy at risk."

In a piece in the Guardian, Barcelona's mayor, Xavier Trias, summed up the vision for an independent Catalonia:

If Catalonia becomes independent, it will be a new kind of state: European, open for trade, cosmopolitan and welcoming and protective of its many diverse inhabitants, including the millions of people from around the world who have come in recent decades … It is wrong, and divisive, to oppose this vision.

Ahead of Scotland's referendum, FC Barcelona, one of the world's most popular soccer clubs and an institution of Catalan nationalism in its own right, will wear Catalonia's nationalist yellow-and-red bars rather than its traditional "blaugrana" uniform for the first time in its home stadium. The team is hosting Athletic Bilbao, the most popular club from the Basque country, another Spanish region contemplating secession.