Oh my, we got someone who asked for it!
Battle of Las Navas de Tolosa, 1212. An alliance of the 3 Christian kingdoms fights the Moors in the canyon called Despeñaperros (lit. “drop them dogs down the side of the mountain”; I’ve been through it on the old road and it’s not a good road for people with weak tummies). The moor general Miramamolin is in a large tent surrounded by warrior-slaves, guys whose only purpose in life is to fight; they are chained in place. The gigantic Navarrese king, Sancho VII (the Strong) reaches the tent and rips the chains off the floor, freeing the slaves who, awed by his size and strength, stop fighting.
He brought back as mementos: twenty of those warriors who’d asked to join him, a length of the chains and the emerald that had decorated Miramamolin’s turban. The chains and emerald are kept in the museum at Roncesvalles (the point where the Road to Santiago enters Navarra from France and where Sancho and his French-born wife are buried). The emerald is over 2" wide, circular and buffed but uncut; it’s not a “true emerald” but a “mother emerald”. This means that it wouldn’t be considered a real emerald by current gemologists, being the wrong crystalographic form, but it’s got tiny real emeralds inside and anyway Miramamolin had paid a bundle for it. The original chains are iron and so black, but the emerald itself is encased in gold and has some golden chains.
The red background is supposed to be for honor unto death and stuff like that; the fact that it makes a nice contrast with the golden chains is irrelevant. We also like to make the joke that, since our flag and shield are blood-red, a Navarrese can never be far from his flag.
As for Aragon: the stripes actually come from Catalonia.
Charlemagne’s possessions included the Marca Catalana, in the NE of Spain (the term “Marquis” comes from “Marca”). The first Counts there were all his vassals. Shortly after the Moors invaded the Peninsula, His Imperial Frankishness took a trip south of the Pyrinees which included a battle in the Marca.
One of the Counts, Wifre el Vellut aka Gofre el Velloso aka Hairy Wilfred of Barcelona, fought very valiantly but fell, wounded by several arrows in a way that meant slow-but-sure death. Charlemagne had him taken to his own tent and told him to ask for anything he could provide; Wifre said “sir, all your knights have their shields, but my people don’t”.*
The Emperor wet his fingers on the Counts blood, turned and passed his hand over a plain golden shield that was there. “With your blood you paid, let your blood be your people’s shield.”
At first, the different Counts from Catalonia were all independent fellows who laid their loyalties wherever they felt like it; the Count of Barcelona was a sort of Primus Inter Pares but there were times when Manresa or Tortosa had more weight. By the year 1000 (earlier but I want to make sure I don’t get spanked for giving a date that’s too early), though, Catalonia had pretty much been absorbed by the Crown of Aragon, mostly through marriages. The bars of Catalonia, being an easy-to-make standard, quite unique, and easy to see, became the bars of Aragon.
Every part of Spain that’s ever been part of the Crown of Aragon includes some variants of the Bars in its flag and its coat of arms.
- In English one speaks of the coat of arms; in Spanish it’s the “shield”, same word as for the actual chunk of stuff you use for defense.