Catalonia has been settled by the Phoenicians, the Etruscans and the Greeks, who were mainly in the coastal areas of Rosas and Empuries (above). Then came the Romans, who built more settlements and infrastructure. Catalonia remained a part of the Roman Empire until it was conquered by the Visigoths in the fifth century.

Catalonia was conquered by Arabs in 711 AD. The Frankish king Charlemagne stopped their advance at Tours on the Loire River and, by 759, the north of Catalonia was once again Christian. In 1137, the counties that made up Catalonia entered an alliance with the Crown of Aragon.

In the 13th century, the institutions of Catalan self-administration were created under the banner of the Generalitat de Catalunya. After the unification of the Crown of Aragon with that of Castile in 1476, Aragon was largely able to keep its autonomic institutions. However, the Catalan revolt — from 1640 to 1659 — saw parts of Catalonia ceded to present-day France.

After the conquest of Barcelona on September 11, 1714, by the Bourbon King Phillip V, Catalan instuitutions were dissolved and self-administration came to an end. Every year, on September 11, Catalans commemorate the end of their right to autonomy.

After the abdication of King Amadeo I of Spain, the first Spanish Republic was declared in February 1873. It lasted barely a year. The supporters of the Republic were split – one group supporting the idea of a centralized republic, the others wanting a federal system. Pictured here is Francisco Pi i Maragall, a supporter of federalism and one of five presidents of the short-lived republic.

Catalonia sought to establish a new state within the Spanish republic, but this only served to exacerbate the differences between republicans, ultimately dividing and weakening them. In 1874, the monarchy and the House of Bourbon (led by King Alfonso XII, pictured here) took the helm.

Between 1923 — with the support of the monarchy, the army and the church — General Primo de Rivera declared a dictatorship. Catalonia became a center of opposition and resistance. After the end of the dictatorship, the politician Francesc Macia (pictured here) successfully pressed for important rights of autonomy for Catalonia.

In the Second Spanish Republic, Catalan lawmakers worked on the Statute of Autonomy of Catalonia. This was approved by the Spanish parliament in 1932. Francesc Macia was elected president of the Generalitat of Catalonia by the Catalan parliament. However, the victory of Franco at the end of the Spanish Civil War (1936 to 1939) put an end to all that.

The Franco regime ruled with an iron rod. Political parties were banned and the Catalan language and culture were surpressed.

After the first parliamentary elections that followed the end of the Franco dictatorship, the Generalitat of Catalonia was provisionally restored. Under the democratic Spanish constitution of 1978, Catalonia was given a new Statute of Autonomy just a year later.

The new Statute of Autonomy recognized the autonomy of Catalonia and the importance of the Catalan language. In comparison to the 1932 statute, it was enhanced in the fields of culture and education but curtailed when it came to the realm of justice. Pictured here is Jordi Pujol, the long-time head of the government of Catalonia after the dictatorship.

A desire for independence has grown stronger in recent years. In 2006, Catalonia was given a new statute that broadened the Catalan government's powers. However, it lost these after a complaint by the conservative Popular Party to the Constitutional Court of Spain.

A referendum on independence was already envisaged for November 9, 2014. The first question was "Do you want Catalonia to become a state?" In the case of an affirmative answer, the second question was posed: "Do you want this state to be independent?" However, the Constitutional Court suspended the vote.

Since January 2016, Carles Puigdemont has been president of the Catalan government. He proceeded with the separatist course of his predecessor Artur Mas and called the new referendum for October 1, 2017. Spanish Prime Minister Mariano Rajoy dismissed this as unconstitutional.

Security forces used batons and fired rubber bullets in an attempt to disperse the crowds. Many were injured. "We were forced to do what we did not wish to do," said Spanish government delegate to Catalonia, Enric Millo. "Puigdemont and his team are solely responsible" for the violence, he added.

Supporters of an independent Catalonia have long accused the central government of denying the will of the people. At this Barcelona rally ahead of the Sunday vote, one of the protesters holds up a picture of late Spanish dictator Francisco Franco kissing the current Prime Minister Mariano Rajoy.

Anti-independence protesters also took to the streets of Barcelona to show their support for a united Spain. In this photo from Saturday, one of them is shouting at a member of the Catalan regional police force, called Mosso d'Esquadra.

Ahead of the referendum, activists distributed voting material and paraphernalia despite the government ban. The Catalan authorities in Barcelona said that the vote would be legally binding.

Rajoy's government has rejected the independence referendum as unconstitutional and pledged to shut down voting. Many opponents of Catalan separatism gathered in Madrid on Sunday, chanting "Viva Espana" and "Catalonia is Spain."

Spanish authorities deployed thousands of extra police to the region. They received orders to prevent voting and seize ballot boxes. Security forces patrolled the polling stations in the early hours of Sunday morning.

Activists decided to camp out at the polling stations in case police tried to shut the venues down.

Reports of violence started coming in early on Sunday. Scuffles broke out near the city of Girona, where Catalan regional leader Carles Puigdemont was due to cast his ballot. The police raided the polling station, forcing Puigdemont to vote at a different location.

Pro-independence protesters tried to prevent the police from confiscating ballots and ballot boxes. Catalan officials say that, despite Madrid's efforts, 73 percent of about 6,000 polling stations were open on Sunday.

Pro-independence activists were instructed to "practice passive resistance" while attempting to delay the security forces from disrupting the vote. The movement supplied their protesters with red carnations to give to the officers. However, police reported they were also pelted with stones.

On Sunday morning, Catalan officials said people could also use ballots they printed at home, and vote at any open polling station if their designated booth was closed.

While a June poll indicated that a majority of Catalans would be in favor of remaining within Spain, it also showed that independence supporters were far more likely to vote on a referendum. Madrid's crackdown is sure to fan the flames of the independence movement.