As you walk around Barcelona or travel throughout Catalonia, you'll see two different Catalan flags hanging from balconies and official buildings.
The one with four red stripes on a yellow background is the Senyera and the one with an added star, which is normally white on a blue background, is the Estelada.
So what does each of them mean and what's the difference between them?
La Senyera is the official flag of the Spanish Autonomous Communities of Catalonia, Aragón, the Balearic Islands, Valencia and the historically Catalan-speaking city of Alghero in Sardinia. It is also included on the flags or coats of arms of Pyrénées-Orientales, Provence-Alpes-Côte d'Azur, the flag of Roussillon, Capcir, Vallespir and Provence in France and is a quarter of the coat of arms of Andorra.
All these territories were, at one time or other, part of the Crown of Aragón, which was ruled by the Count of Barcelona, and today the parts of these territories where the Catalan language is still spoken are known as the Països Catalans or Catalan countries.
The first appearance of La Senyera dates back to the tomb of Ramon Berenguer II, Count of Barcelona, who died in 1082, and later appears in the seals of Ramon Berenguer IV, Count of Barcelona and of Provence in 1150 before being adopted in documents and coats of arms throughout what was to become the Catalan-Aragonese Empire.
Although the four bars probably date back to a simple practical heraldic symbol the legend behind La Senyera's creation is worth recounting.
The story goes that Count of Barcelona and many other Catalan territories Guifré el Pilós or Wilfred the Hairy was fighting alongside the coincidentally named Carles el Calb or Charles the Bald, the Frankish ruler, against the Moorish Governor of Lleida, Lobo ibn Mohammed.
Wilfred the Hairy was seriously wounded and as Catalonia did not exist yet, it did not have a flag so the next day the Catalan troops would have to go into battle without their leader or a standard to rally to.
Before the battle began, Charles the Bald plunged his hands in Wilfred's wound and wiped them across a golden shield and, with the shield, held high led the Catalan troops to victory.
For this reason, the four red stripes on a golden background of the Catalan flag are known as Els Quatre Dits de Sang ot The Four Fingers of Blood.
The full name of the Estelada is La Senyera Estelada, which means starred flag, and is normally a Senyera with a white star superimposed on a blue triangle at the top although a red star on a yellow background is also common.
It is an unofficial flag and is generally waved by supporters of Catalonia's independence from Spain, which is why you see so many of them hanging from balconies in Barcelona and the rest of Catalonia at the moment.
Inspired by the stars on the Puerto Rican and Cuban flags, who gained independence from Spain in 1898 and 1902 respectively, Catalan independentists began including stars on their symbols from the early 20th century onwards.
Ties between independent Cuba and the separatists were deep and longstanding (and Cuba today still has a small Catalan community of 3600).
The first known use of the blue Estelada was on a pamphlet for the 1918 Diada or Catalan National Day and it was probably designed by Vicenç Albert Ballester i Camps.
From then on it became closely associated with Catalan independentism and future Catalan President Francesc Macià waved one during during his failed invasion of Prats de Molló in 1926, for example.
In the current Catalan independence movement, the “classic” white-star-on-blue-triangle flag is very much back in vogue, alongside a large number of variants.
Throughout the 1930s, the tradition began of showing just the blue part of the Estelada at independentist funerals and throughout Franco's dictatorship, the flag was used by the Front Nacional de Catalunya (FNC).
Due to FNC splinter group PSAN, since 1968, the red star on
a yellow background, which is known as the Estelada Vermella or Red Estelada, has increasingly become associated with left-wing,
libertarian and republican ideas.
Since the return of democracy, the Estelada has remained the symbol of freedom for Catalonia and in the current push for independence that has been accelerating since 2010, it has become ubiquitous both as a flag and as grafitti around Catalonia.
However, it should be pointed out that the Estelada is a temporary symbol and once independence from Spain is gained, the Senyera will be the national flag of Catalonia.
Although the position of FC Barcelona on Catalan independence is complex from an institutional view, many supporters clearly back the Catalan independence process and make this clear throughout games.
This has led to the Estelada Blaugrana, as well as an Estelada Perica waved by pro-independence supporters of RCD Espanyol.
Early in the 2015-16 season, FC Barcelona was fined by UEFA for waving Estelada flags at matches and shouting Independència! at minute 17.14 of each half in commemoration of the fall of Barcelona to the troops of Castilian king, Felipe V, in 1714.
Things came to a head in May 2016, when Estelades were banned from the Copa del Rei final because, according to the government delegate in Madrid, Concepción Dancausa, they incited violence.
A court ruling overturned the ban and in the Barça supporters were able to take Esteladas to the game against Sevilla in Atlético de Madrid's Vicente Calderón stadium on May 22nd 2016.