I suggest the Wikipedia article on the topic.
The Basque right wing is in many ways more Spanish than the Spaniards (more Catholic, more traditionalist). This is explained throgh their association with Carlism. PNV has no small number of skeletons in their closet regarding Carlist cooperation with Franco during the civil war.
The Spanish language originated near the Basque country, and it is theorised that some peculiar [with respect to other romanic languages] phonetic and grammatical features have their origin in Basque.
There is an Episode in Don Quixote in which him and Sancho meet a Biscayan. This is an invaluable peek into the atttitudes of Castilliand towards Basques around 1600. Cervantes makes fun of his accent, for instance.
Basque nationalism in its present form was invented by Sabino Arana in the late 19th century. IMHO there is no question that there is a distinct Basque people, but they have been part of Spain since the very beginning and not particularly "oppressed". I would blame the Bourbon kings and then Franco for the real or perceived grievances at the core of the current "Basque conflict", but that is a topic for my planned diary on the suppression of the Spanish nationalities.
Hope that helps. guaranteed to evoke a violent reaction from police is to challenge their right to "define the situation." --- David Graeber citing Marc Cooper
A lot of mainstream Catalan and Basque nationalism is related to the nationalism of other wealthy regions (like Northern Italy, for instance). ETA is different: it self-describes as socialist and has its roots in anti-fascist (anti-Franco) resistance. guaranteed to evoke a violent reaction from police is to challenge their right to "define the situation." --- David Graeber citing Marc Cooper
