By Nigel Davies
BARCELONA, Spain (Reuters) - Independence for Catalonia may seem like romantic folly to outsiders. The Spanish region must reach back to the Middle Ages to find historic grounds for a separate territory.
It isn't so much cultural identity that has breathed new life into the secession movement, but frustration over taxes, unemployment and recession.
An increasing number of the most ardent supporters of Catalan independence do not even have roots in the region.
They are immigrants from the rest of Spain who have embraced separatism because they believe Catalonia, historically an economic powerhouse, would be more prosperous on its own.
Economists cast doubts on that argument. But, right or wrong, these Catalan converts will be key voters on Sunday when the region chooses a new government in an election on Sunday that has become a proxy for a referendum on independence.
Take 72-year-old Josep Periera, who moved to Catalonia during a mid-century wave of immigration from Andalusia, a relatively poor agricultural region in Spain's south.
When he moved to Catalonia decades ago he was called Jose. He has changed his name to the Catalan equivalent, Josep, and completely integrated.
"Only three years ago I wasn't pro-independence. But we can't take this any more," he told Reuters at a rally for Catalan President Artur Mas, who is seeking re-election after converting to the independence cause in September following a massive demonstration by secessionists.
CiU and three other pro-independence parties from across the political spectrum are expected to take a two-thirds majority in the regional assembly, known as the Parlament.
That majority will back Mas's pledge to call a referendum on independence in defiance of Spain's constitution.
With Spain in the grip of recession and unemployment running at 25 percent, Catalans are increasingly disgruntled that Madrid refuses to renegotiate the current tax system.
They say Catalonia would be able to invest in job creation if 16 billion euros of its tax revenue did not stay with the central government each year.
Among Catalonia's 7.5 million people are 3 million with roots outside the region. Polls show that more and more of those immigrants or children of immigrants support statehood.
A poll by the official Catalan statistics agency this month showed 80 percent of adults whose parents are Catalans support independence. And 41 percent of adults with non-Catalan parents also want independence - up from 25 percent in June 2011.
Those converts have helped to push overall support for independence higher than 50 percent for the first time.
In the past, Andalusian immigrants in Spanish-speaking "ghettos" on the edge of Barcelona suffered discrimination and were even called "xarnego", a Catalan word for a kind of dog.
But their children speak Catalan and yearn for the years when the region created work for people from all over Spain.
"I'm a circumstantial independence supporter because of the brutal effects of the crisis and the fact Spain has been plundering Catalonia's wealth for years," said Lluis Val, 32. His parents moved here decades ago for work but he now has trouble finding well-paid work.
Salvador Garcia Ruiz, a 36-year-old economist, is the son of Andalusian immigrants. Like many Catalans he feels the rest of Spain has misunderstood sentiment in the region.
"People don't understand that we are not against Spain, we are just pro-independence, and that's why now it has become mainstream. We still want to have a good relationship with Spain," he said.
Many Catalans recognize that full independence may be impossible to achieve because the region would probably have to leave the European Union - risking economic disaster - and because the rest of Spain will put up a huge fight for unity.
But polls show a large majority would like the right to vote in a referendum. A pro-independence march in September of around one million people reflected the growing movement.
"An avalanche of people on the street made this happen and the only thing we want is a referendum so at least we can express what we want," said supermarket worker Miriam Cascales, 32.
Secessionism is particularly strong among young voters like Cascales. According to pollster Metroscopia, around 60 percent of voters between 18 and 35 back the cause. The jobless rate is highest among young people.
"The debate has moved away from being a pure debate about the independence of Catalonia to a wider economic debate," said Maria Jose Hierro, political scientist at the Pompeu Fabra University.
Polls show that support for independence drops when people factor in the possibility of having to leave the EU.
And plenty of Catalans, immigrants and natives, are upset at the prospect of having to choose between being Catalan or Spanish, since they feel both.
Josep, a 52-year-old business owner, said he supported independence but recognized that many with origins in other parts of Spain were confused.
"Many don't feel fully Spanish or fully Catalan. There is a big mass of people that don't know who to vote for," he said.
He said he did not want to give his surname as he was worried about threats of commercial boycotts from the rest of Spain due to the rising independence fervor.
(Additional reporting by Braden Phillips; Editing by Fiona Ortiz)