*** A Brief History of al-Andalus ***
From about 600 to about 1600
-- PRIOR TO THE SEVENTH CENTURY --
By the 6th century Roman Spain was "an invalid lapsing into terminal agony". The city of Rome in Italy had fallen to repeated onslaughts and the Roman Empire had moved to the far eastern edge of Europe in Byzantium, where the primary language was Greek, not Latin.
A caste system had been established by Emperor Diocletian 300 years before to impose "stability" by ordaining that the occupation of the father would be the occupation of his sons. While not enforced completely, it was used as desired, and continued to exert influence on the local culture.
The old Roman middle class had almost disappeared, and fine Roman engineering of roads, sewers, aquaducts, etc., had fallen into disrepair. Cities were packed with the unemployed who were entertained by "circuses", and on the dole - and if not, they rioted.
The small number of those who owned 25 acres of land or more paid most of the taxes.
The population was mixed culturally and religiously.
Prior to the arrival of the Romans, there were indigenous Spanish people, Iberian Celts, and Iberians of Phoenician descent. In fact, many of Spain's major ports and coastal cities even today were founded by the Phoenicians and were a part of the subsequent Punic culture, against which the Romans fought so viciously.
After the Jerusalem rebellion put down by the Romans (in the 1st c.?), but because Judaism was a religio licita, a legal religion, Jews were welcomed around the Empire. Over one million had settled in Roman Iberia.
Early in the 4th century, all Romans became officially Christian by royal fiat of Emperor Constantine I, called "the Great" (Flavius Valerius Aurelius Constantinus, b. 288, ruled 324-337), who also named Constantinople as the new capitol of Rome. The Church, however, never fully trusted the Roman aristocrats, whom they considered to have strong Pagan predilictions and persecution of suspected backsliders was fierce.
The Vandals, after whom the Arabs were to name Spain al-Andalus, came in via the Beléaric islands and laid waste to the countryside around Cartegena in the early 5th century, until the Romans bribed them to go to the Maghrib in North Africa in 429. They eventually sacked Rome in 455, but lost out when the Goths sacked Rome and took over Italy in 470.
Later in the 5th century, the Germanic Suevi tribe "scorched the Galician earth in a 60 year terror" that ended when the Visigoths ousted them.
The Visigoths, the Western branch of the Goths, had a kingdom in France from 418-507. They had converted to Christianity half a century before they crossed the Pyrenees into Spain in 456, following the Arian heresy, which cast doubt on the divinity of Jesus and which considered the concept of the Trinity as a dilution of strict monotheism. Because of these powerful theological differences, there were intense hostilities between these invading followers of the doctrines of Bishop Arius and the orthodox Christians already in Spain.
Toledo was the Visigoth capital. Visigoth kings, "who succeeded one another with great rapidity", tried to establish order, but didn't get far, as they were faced by constant invasions or insurrections by hostile groups, including other Visigoths. When the Visigoths were defeated by the Muslims around 711, the Suevi came back to Galicia and Asturias.
In Roman Iberia, thousands of slaves might belong to one patron. By the dawn of the seventh century, those slaves, many of whom were Germanic, joined with their kin, who had become the real masters of Spain.
-- SEVENTH CENTURY --
All the Spanish Christians, regardless of their sect, were unified in their intolerance of Jews. Many laws were passed restricting Jews. Although they were not always followed or enforced, new anti-Jewish laws made annually.
Since eventually every Visigoth king decided to stamp out Judaism, this period was a reign of terror for the Jews of Spain. However, there was one mitigating factor. The Visigoths fought among themselves over positions of power with great frequency. When one got power, he would banish or kill his predecessor's friends and followers. This often distracted them from their persecution of the Jews.